Journal tags: frontend

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Design engineering on the Clearleft podcast

If you’re subscribed to the Clearleft podcast, then the latest episode is winging its way through the ether to your podcast software. The topic is one close to my heart: design engineering.

I wrote about this role back in February. I think my fervour comes across in that post and you can probably hear it in the podcast episode too.

As ever, I end up asking the question, “So what exactly is insert topic of the podcast episode here?”

I’ve got some smart folks answering that question. There’s an excerpt from Tobias Ahlin’s talk at this year’s UX Fest. And when I interviewed Adekunle Oduye for a previous episode on prototyping, we also discussed design engineering so I pulled out the relevant bits. But the bulk of the episode features the voice of Trys Mudford.

As you can gather from the many posts on Trys’s blog, he has a lot to say on the topic of design engineering. Luckily for me, he says it all with a clear, articulate delivery—the perfect podcast guest!

This episode finishes with a call to action (oh, the synergy!). If, after listening to 23 minutes of discussion on design engineering, you find yourself thinking “Hey, I think I might be a design engineer!”, then you should definitely head along to this job opening at Clearleft:

We’re currently looking for a design-friendly front-end developer with demonstrable skills in pattern-based prototyping and production.

Have a listen to episode two of season three of the Clearleft podcast and if you like what you hear, come and join us!

Accessibility testing

I was doing some accessibility work with a client a little while back. It was mostly giving their site the once-over, highlighting any issues that we could then discuss. It was an audit of sorts.

While I was doing this I started to realise that not all accessibility issues are created equal. I don’t just mean in their severity. I mean that some issues can—and should—be caught early on, while other issues can only be found later.

Take colour contrast. This is something that should be checked before a line of code is written. When designs are being sketched out and then refined in a graphical editor like Figma, that’s the time to check the ratio between background and foreground colours to make sure there’s enough contrast between them. You can catch this kind of thing later on, but by then it’s likely to come with a higher cost—you might have to literally go back to the drawing board. It’s better to find the issue when you’re at the drawing board the first time.

Then there’s the HTML. Most accessibility issues here can be caught before the site goes live. Usually they’re issues of ommission: form fields that don’t have an explicitly associated label element (using the for and id attributes); images that don’t have alt text; pages that don’t have sensible heading levels or landmark regions like main and nav. None of these are particularly onerous to fix and they come with the biggest bang for your buck. If you’ve got sensible forms, sensible headings, alt text on images, and a solid document structure, you’ve already covered the vast majority of accessibility issues with very little overhead. Some of these checks can also be automated: alt text for images; labels for inputs.

Then there’s interactive stuff. If you only use native HTML elements you’re probably in the clear, but chances are you’ve got some bespoke interactivity on your site: a carousel; a mega dropdown for navigation; a tabbed interface. HTML doesn’t give you any of those out of the box so you’d need to make your own using a combination of HTML, CSS, JavaScript and ARIA. There’s plenty of testing you can do before launching—I always ask myself “What would Heydon do?”—but these components really benefit from being tested by real screen reader users.

So if you commission an accessibility audit, you should hope to get feedback that’s mostly in that third category—interactive widgets.

If you get feedback on document structure and other semantic issues with the HTML, you should fix those issues, sure, but you should also see what you can do to stop those issues going live again in the future. Perhaps you can add some steps in the build process. Or maybe it’s more about making sure the devs are aware of these low-hanging fruit. Or perhaps there’s a framework or content management system that’s stopping you from improving your HTML. Then you need to execute a plan for ditching that software.

If you get feedback about colour contrast issues, just fixing the immediate problem isn’t going to address the underlying issue. There’s a process problem, or perhaps a communication issue. In that case, don’t look for a technical solution. A design system, for example, will not magically fix a workflow issue or route around the problem of designers and developers not talking to each other.

When you commission an accessibility audit, you want to make sure you’re getting the most out of it. Don’t squander it on issues that you can catch and fix yourself. Make sure that the bulk of the audit is being spent on the specific issues that are unique to your site.

Stakeholders of styling

When I wrote about the new accent-color property in CSS, I pondered how much control a web developer should have over styling form controls:

Who are we to make that decision? Shouldn’t the user’s choice take primacy over our choices?

But then again, where do we draw the line? We’re allowed over-ride link colours. We’re allowed over-ride font choices.

Ultimately, I came down on the side of granting authors more control:

If developers don’t get a standardised way to customise native form controls, they’ll just recreate their own over-engineered versions.

This question of “who gets to decide?” used to be much more prevelant in the early days of the web. One way to think about this is that there are three stakeholders involved in the presentation of a web page:

  1. The author of the page. “Author” is spec-speak for designer or developer.
  2. The user.
  3. The browser, or user agent. A piece of software tries to balance the needs of both author and user. But, as the name implies, the user takes precedence.

These days we tend to think of web design a single-stakeholder undertaking. The author decides how something should be presented and then executes that decision using CSS.

But as Eric once said, every line of you CSS you write is a suggestion to the browser. That’s not how we think about CSS though. We think of CSS like a series of instructions rather than suggestions. Never mind respecting the user’s preferences; one of the first things we do is reset all the user agent’s styles.

In the early days of the web, more consideration was given to the idea of style suggestions rather than instructions. Heck, users could always over-ride any of your suggestions with their own user stylesheet. These days, users would need to install a browser extension to do the same thing.

The first proposal for CSS had a concept called “influence”:

h2.font.size = 20pt 40%

Here, the requested influence is reduced to 40%. If a style sheet later in the cascade also requests influence over h2.font.size, up to 60% can be granted. When the document is rendered, a weighted average of the two requests is calculated, and the final font size is determined.

I think the only remnant of “influence” left in CSS is accidental. It’s in the specificity of selectors …and the !important declaration.

I think it’s a shame that user stylesheets are no longer a thing. But I get why they were dropped from browsers. They date from a time when it was mostly nerds using the web, before “regular folks” came on board. I understand why it became a little-used feature, suitable for being dropped. But the principle of it still rankles slightly.

But in recent years there has been a slight return to the multi-stakeholder concept of styling websites. Thanks to prefers-reduced-motion and prefers-color-scheme, a responsible author can choose to bow to the wishes of the user.

I was reminded of this when I added a dark mode to my website:

Y’know, when I first heard about Apple adding dark mode to their OS—and also to CSS—I thought, “Oh, great, Apple are making shit up again!” But then I realised that, like user style sheets, this is one more reminder to designers and developers that they don’t get the last word—users do.

Accent all areas

Whenever a new version of Chrome comes out, there’s an accompanying blog post listing what’s new. Chrome 93 just came out and, sure enough, Pete has written a blog post about it.

But what I think is the most exciting addition to the browser isn’t listed.

What is this feature that’s got me so excited?

Okay, I’ve probably oversold it now because actually, it looks like a rather small trivial addition. It’s the accent-color property in CSS.

Up until now, accent colour was controlled by the operating system. If you’re on a Mac, go to “System Preferences” and then “General”. There you’ll see an option to change your accent colour. Try picking a different colour. You’ll see that change cascade down into the other form fields in that preference pane: checkboxes, radio buttons, and dropdowns.

Your choice will also cascade down into web pages. Any web page that uses native checkboxes, radio buttons and other interface elements will inherit that colour.

This is how interface elements are supposed to work. The browser inherits the look’n’feel of the inputs from the operating system.

That’s the theory anyway. In practice, form elements—such as dropdowns—can look different from browser to browser, something that shouldn’t be happening if the browsers are all inheriting from the operating system.

Anyway, it’s probably this supposed separation of responsibility between browser and operating system which has led to the current situation with form fields and CSS. Authors can style form fields up to a point, but there’s always a line that you don’t get to cross.

The accent colour of a selected radio button or a checkbox has historically been on the other side of that line. You either had to accept that you couldn’t change the colour, or you had to make your own checkbox or radio button interface. You could use CSS to hide the native element and replace it with an image instead.

That feels a bit over-engineered and frankly kind of hacky. It reminds me of the bad old days of image replacement for text before we had web fonts.

Now, with the accent-color property in CSS, authors can over-ride the choice that the user has set at the operating system level.

On the one hand, this doesn’t feel great to me. Who are we to make that decision? Shouldn’t the user’s choice take primacy over our choices?

But then again, where do we draw the line? We’re allowed over-ride link colours. We’re allowed over-ride font choices.

Ultimately I think it’s a good thing that authors can now specify an accent colour. What makes me think that is the behaviour that authors have shown if they don’t have this ability—they do it anyway, and in a hackier manner. This is why I think the work of the Open UI group is so important. If developers don’t get a standardised way to customise native form controls, they’ll just recreate their own over-engineered versions.

The purpose of Open UI to the web platform is to allow web developers to style and extend built-in web UI controls, such as select dropdowns, checkboxes, radio buttons, and date/color pickers.

Trying to stop developers from styling checkboxes and radio buttons is like trying to stop teenagers from having sex. You might as well accept that it’s going to happen and give them contraception so they can at least do it safely.

So I welcome this new CSS condom.

You can see accent-color in action in this demo. Change the value of the accent-color property to see the form fields update:

:root {
  accent-color: rebeccapurple;
}

Applying it at the document level like that will make it universal, but you can also use the property on an element-by-element basis using whatever selector you want.

That demo works in Chrome and Edge 93, the current release. It also works in Firefox 92, which literally just landed (like as I was writing this blog post, support for accent-color magically arrived!).

As for Safari, well, who knows? If Apple published a roadmap, then developers would have a clue when to expect a property like this to land. But we mere mortals cannot be trusted with such important hush-hush information.

In the meantime, keep an eye on Can I Use. And lack of support on one browser is no reason not to use accent-color anyway. It’s a progressive enhancement. Add it to your CSS today and it will work in more browsers in the future.

SafarIE

I was moaning about Safari recently. Specifically I was moaning about the ridiculous way that browser updates are tied to operating system updates.

But I felt bad bashing Safari. It felt like a pile-on. That’s because a lot of people have been venting their frustrations with Safari recently:

I think it’s good that people share their frustrations with browsers openly, although I agree with Baldur Bjarnason that’s good to avoid Kremlinology and the motivational fallacy when blogging about Apple.

It’s also not helpful to make claims like “Safari is the new Internet Explorer!” Unless, that is, you can back up the claim.

On a recent episode of the HTTP 203 podcast, Jake and Surma set out to test the claim that Safari is the new IE. They did it by examining Safari according to a number of different measurements and comparing it to the olden days of Internet Explorer. The result is a really fascinating trip down memory lane along with a very nuanced and even-handed critique of Safari.

And the verdict? Well, you’ll just to have to listen to the podcast episode.

If you’d rather read the transcript, tough luck. That’s a real shame because, like I said, it’s an excellent and measured assessment. I’d love to add it to the links section of my site, but I can’t do that in good conscience while it’s inaccessible to the Deaf community.

When I started the Clearleft podcast, it was a no-brainer to have transcripts of every episode. Not only does it make the content more widely available, but it also makes it easier for people to copy and paste choice quotes.

Still, I get it. A small plucky little operation like Google isn’t going to have the deep pockets of a massive corporation like Clearleft. But if Jake and Surma were to open up a tip jar, I’d throw some money in to get HTTP 203 transcribed (I recommend getting Tina Pham to do it—she’s great!).

I apologise for my note of sarcasm there. But I share because I care. It really is an excellent discussion; one that everyone should be able to access.

Update: the bug with that episode of the HTTP 203 podcast has been fixed. Here’s the transcript! And all future episodes will have transcripts too:

Upgrade paths

After I jotted down some quick thoughts last week on the disastrous way that Google Chrome rolled out a breaking change, others have posted more measured and incisive takes:

In fairness to Google, the Chrome team is receiving the brunt of the criticism because they were the first movers. Mozilla and Apple are on baord with making the same breaking change, but Google is taking the lead on this.

As I said in my piece, my issue was less to do with whether confirm(), prompt(), and alert() should be deprecated but more to do with how it was done, and the woeful lack of communication.

Thinking about it some more, I realised that what bothered me was the lack of an upgrade path. Considering that dialog is nowhere near ready for use, it seems awfully cart-before-horse-putting to first remove a feature and then figure out a replacement.

I was chatting to Amber recently and realised that there was a very different example of a feature being deprecated in web browsers…

We were talking about the KeyboardEvent.keycode property. Did you get the memo that it’s deprecated?

But fear not! You can use the KeyboardEvent.code property instead. It’s much nicer to use too. You don’t need to look up a table of numbers to figure out how to refer to a specific key on the keyboard—you use its actual value instead.

So the way that change was communicated was:

Hey, you really shouldn’t use the keycode property. Here’s a better alternative.

But with the more recently change, the communication was more like:

Hey, you really shouldn’t use confirm(), prompt(), or alert(). So go fuck yourself.

Browsers

I mentioned recently that there might be quite a difference in tone between my links and my journal here on my website:

’Sfunny, when I look back at older journal entries they’re often written out of frustration, usually when something in the dev world is bugging me. But when I look back at all the links I’ve bookmarked the vibe is much more enthusiastic, like I’m excitedly pointing at something and saying “Check this out!” I feel like sentiment analyses of those two sections of my site would yield two different results.

My journal entries have been even more specifically negative of late. I’ve been bitchin’ and moanin’ about web browsers. But at least I’m an equal-opportunities bitcher and moaner.

I wish my journal weren’t so negative, but my mithering behaviour has been been encouraged. On more than one occasion, someone I know at a browser company has taken me aside to let me know that I should blog about any complaints I might have with their browser. It sounds counterintuitive, I know. But these blog posts can give engineers some ammunition to get those issues prioritised and fixed.

So my message to you is this: if there’s something about a web browser that you’re not happy with (or, indeed, if there’s something you’re really happy with), take the time to write it down and publish it.

Publish it on your website. You could post your gripes on Twitter but whinging on Jack’s website is just pissing in the wind. And I suspect you also might put a bit more thought into a blog post on your own site.

I know it’s a cliché to say that browser makers want to hear from developers—and I’m often cynical about it myself—but they really do want to know what we think. Share your thoughts. I’ll probably end up linking to what you write.

Foundations

There was quite a kerfuffle recently about a feature being removed from Google Chrome. To be honest, the details don’t really matter for the point I want to make, but for the record, this was about removing alert and confirm dialogs from cross-origin iframes (and eventually everywhere else too).

It’s always tricky to remove a long-established feature from web browsers, but in this case there were significant security and performance reasons. The problem was how the change was communicated. It kind of wasn’t. So the first that people found out about it about was when things suddenly stopped working (like CodePen embeds).

The Chrome team responded quickly and the change has now been pushed back to next year. Hopefully there will be significant communication before that to let site owners know about the upcoming breakage.

So all’s well that ends well and we’ve all learned a valuable lesson about the importance of communication.

Or have we?

While this was going on, Emily Stark tweeted a more general point about breakage on the web:

Breaking changes happen often on the web, and as a developer it’s good practice to test against early release channels of major browsers to learn about any compatibility issues upfront.

Yikes! To me, this appears wrong on almost every level.

First of all, breaking changes don’t happen often on the web. They are—and should be—rare. If that were to change, the web would suffer massively in terms of predictability.

Secondly, the onus is not on web developers to keep track of older features in danger of being deprecated. That’s on the browser makers. I sincerely hope we’re not expected to consult a site called canistilluse.com.

I wasn’t the only one surprised by this message.

Simon says:

No, no, no, no! One of the best things about developing for the web is that, as a rule, browsers don’t break old code. Expecting every website and application to have an active team of developers maintaining it at all times is not how the web should work!

Edward Faulkner:

Most organizations and individuals do not have the resources to properly test and debug their website against Chrome canary every six weeks. Anybody who published a spec-compliant website should be able to trust that it will keep working.

Evan You:

This statement seriously undermines my trust in Google as steward for the web platform. When did we go from “never break the web” to “yes we will break the web often and you should be prepared for it”?!

It’s worth pointing out that the original tweet was not an official Google announcement. As Emily says right there on her Twitter account:

Opinions are my own.

Still, I was shaken to see such a cavalier attitude towards breaking changes on the World Wide Web. I know that removing dangerous old features is inevitable, but it should also be exceptional. It should not be taken lightly, and it should certainly not be expected to be an everyday part of web development.

It’s almost miraculous that I can visit the first web page ever published in a modern web browser and it still works. Let’s not become desensitised to how magical that is. I know it’s hard work to push the web forward, constantly add new features, while also maintaining backward compatibility, but it sure is worth it! We have collectively banked three decades worth of trust in the web as a stable place to build a home. Let’s not blow it.

If you published a website ten or twenty years ago, and you didn’t use any proprietary technology but only stuck to web standards, you should rightly expect that site to still work today …and still work ten and twenty years from now.

There was something else that bothered me about that tweet and it’s not something that I saw mentioned in the responses. There was an unspoken assumption that the web is built by professional web developers. That gave me a cold chill.

The web has made great strides in providing more and more powerful features that can be wielded in learnable, declarative, forgiving languages like HTML and CSS. With a bit of learning, anyone can make web pages complete with form validation, lazily-loaded responsive images, and beautiful grids that kick in on larger screens. The barrier to entry for all of those features has lowered over time—they used to require JavaScript or complex hacks. And with free(!) services like Netlify, you could literally drag a folder of web pages from your computer into a browser window and boom!, you’ve published to the entire world.

But the common narrative in the web development community—and amongst browser makers too apparently—is that web development has become more complex; so complex, in fact, that only an elite priesthood are capable of making websites today.

Absolute bollocks.

You can choose to make it really complicated. Convince yourself that “the modern web” is inherently complex and convoluted. But then look at what makes it complex and convoluted: toolchains, build tools, pipelines, frameworks, libraries, and abstractions. Please try to remember that none of those things are required to make a website.

This is for everyone. Not just for everyone to consume, but for everyone to make.

Updating Safari

Safari has been subjected to a lot of ire recently. Most of that ire has been aimed at the proposed changes to the navigation bar in Safari on iOS—moving it from a fixed top position to a floaty bottom position right over the content you’re trying to interact with.

Courage.

It remains to be seen whether this change will actually ship. That’s why it’s in beta—to gather all the web’s hot takes first.

But while this very visible change is dominating the discussion, invisible changes can be even more important. Or in the case of Safari, the lack of changes.

Compared to other browsers, Safari lags far behind when it comes to shipping features. I’m not necessarily talking about cutting-edge features either. These are often standards that have been out for years. This creates a gap—albeit an invisible one—between Safari and other browsers.

Jorge Arango has noticed this gap:

I use Safari as my primary browser on all my devices. I like how Safari integrates with the rest of the OS, its speed, and privacy features. But, alas, I increasingly have issues rendering websites and applications on Safari.

That’s the perspective of an end-user. Developers who have to deal with the gap in features are more, um, strident in their opinions. Perry Sun wrote For developers, Apple’s Safari is crap and outdated:

Don’t get me wrong, Safari is very good web browser, delivering fast performance and solid privacy features.

But at the same time, the lack of support for key web technologies and APIs has been both perplexing and annoying at the same time.

Alas, that post also indulges in speculation about Apple’s motives which always feels a bit too much like a conspiracy theory to me. Baldur Bjarnason has more to say on that topic in his post Kremlinology and the motivational fallacy when blogging about Apple. He also points to a good example of critiquing Safari without speculating about motives: Dave’s post One-offs and low-expectations with Safari, which documents all the annoying paper cuts inflicted by Safari’s “quirks.”

Another deep dive that avoids speculating about motives comes from Tim Perry: Safari isn’t protecting the web, it’s killing it. I don’t agree with everything in it. I think that Apple—and Mozilla’s—objections to some device APIs are informed by a real concern about privacy and security. But I agree with his point that it’s not enough to just object; you’ve got to offer an alternative vision too.

That same post has a litany of uncontroversial features that shipped in Safari looong after they shipped in other browsers:

Again: these are not contentious features shipping by only Chrome, they’re features with wide support and no clear objections, but Safari is still not shipping them until years later. They’re also not shiny irrelevant features that “bloat the web” in any sense: each example I’ve included above primarily improving core webpage UX and performance. Safari is slowing that down progress here.

But perhaps most damning of all is how Safari deals with bugs.

A recent release of Safari shipped with a really bad Local Storage bug. The bug was fixed within a day. Yay! But the fix won’t ship until …who knows?

This is because browser updates are tied to operating system updates. Yes, this is just like the 90s when Microsoft claimed that Internet Explorer was intrinsically linked to Windows (a tactic that didn’t work out too well for them in the subsequent court case).

I don’t get it. I’m pretty sure that other Apple products ship updates and fixes independentally of OS releases. I’m sure I’ve received software updates for Keynote, Garage Band, and other pieces of software made by Apple.

And yet, of all the applications that need a speedy update cycle—a user agent for the World Wide Web—Apple’s version is needlessly delayed by the release cycle of the entire operating system.

I don’t want to speculate on why this might be. I don’t know the technical details. But I suspect that the root cause might not be technical in nature. Apple have always tied their browser updates to OS releases. If Google’s cardinal sin is avoiding anything “Not Invented Here”, Apple’s downfall is “We’ve always done it this way.”

Evergreen browsers update in the background, usually at regular intervals. Firefox is an evergreen browser. Chrome is an evergreen browser. Edge is an evergreen browser.

Safari is not an evergreen browser.

That’s frustrating when it comes to new features. It’s unforgivable when it comes to bugs.

At least on Apple’s desktop computers, users have the choice to switch to a different browser. But on Apple’s mobile devices, users have no choice but to use Safari’s rendering engine, bugs and all.

As I wrote when I had to deal with one of Safari’s bugs:

I wish that Apple would allow other rendering engines to be installed on iOS devices. But if that’s a hell-freezing-over prospect, I wish that Safari updates weren’t tied to operating system updates.

Doing the right thing for the wrong reasons

I remember trying to convince people to use semantic markup because it’s good for accessibility. That tactic didn’t always work. When it didn’t, I would add “By the way, Google’s searchbot is indistinguishable from a screen-reader user so semantic markup is good for SEO.”

That usually worked. It always felt unsatisfying though. I don’t know why. It doesn’t matter if people do the right thing for the wrong reasons. The end result is what matters. But still. It never felt great.

It happened with responsive design and progressive enhancement too. If I couldn’t convince people based on user experience benefits, I’d pull up some official pronouncement from Google recommending those techniques.

Even AMP, a dangerously ill-conceived project, has one very handy ace in the hole. You can’t add third-party JavaScript cruft to AMP pages. That’s useful:

Beleaguered developers working for publishers of big bloated web pages have a hard time arguing with their boss when they’re told to add another crappy JavaScript tracking script or bloated library to their pages. But when they’re making AMP pages, they can easily refuse, pointing out that the AMP rules don’t allow it. Google plays the bad cop for us, and it’s a very valuable role.

AMP is currently dying, which is good news. Google have announced that core web vitals will be used to boost ranking instead of requiring you to publish in their proprietary AMP format. The really good news is that the political advantage that came with AMP has also been ported over to core web vitals.

Take user-hostile obtrusive overlays. Perhaps, as a contientious developer, you’ve been arguing for years that they should be removed from the site you work on because they’re so bad for the user experience. Perhaps you have been met with the same indifference that I used to get regarding semantic markup.

Well, now you can point out how those annoying overlays are affecting, for example, the cumulative layout shift for the site. And that number is directly related to SEO. It’s one thing for a department to over-ride UX concerns, but I bet they’d think twice about jeopardising the site’s ranking with Google.

I know it doesn’t feel great. It’s like dealing with a bully by getting an even bigger bully to threaten them. Still. Needs must.

Work at Clearleft

A little while back, I wrote about how much I like the job description of a design engineer. I still have issues with the “engineer” part, but overall it’s a great way to describe a front-end developer who works on the front of the front end: the outputs that end users interact with: HTML, CSS, and JavaScript. If it’s delivered in a web browser, then it’s design engineering.

Perhaps you also prefer the front of the front end to the back of the front end. Perhaps you also like to spend your time thinking about resilience, performance, and accessibility rather than build pipelines and frameworks. Perhaps you’d like to work with like-minded people.

Clearleft is hiring a midweight design engineer. Perhaps it’s you.

If you’d like to use your development talents in the service of good design, you should apply. And remember, you’d be working for yourself: Clearleft is an employee-owned agency.

You don’t have to be based in Brighton. You can work remotely, although we’re expecting that a monthly face-to-face gathering will become the norm after The Situation ends. So if you’re based somewhere like London, that would work out nicely. That said, if you’re based somewhere like London, this might also be the ideal opportunity to make a move to the seaside.

You do have to be eligible to work in the UK. Alas, that pool has shrunk somewhat. Thanks, Brexit.

Perhaps you think you’re not qualified. Apply anyway. You’ve got nothing to lose.

Perhaps this role isn’t for you, but you know someone who might fit the bill. Please tell them. Spread the word.

We’d especially love to hear from people under-represented in design and technology.

Come and work with us.

Numbers

Core web vitals from Google are the ingredients for an alphabet soup of exlusionary intialisms. But once you get past the unnecessary jargon, there’s a sensible approach underpinning the measurements.

From May—no, June—these measurements will be a ranking signal for Google search so performance will become more of an SEO issue. This is good news. This is what Google should’ve done years ago instead of pissing up the wall with their dreadful and damaging AMP project that blackmailed publishers into using a proprietary format in exchange for preferential search treatment. It was all done supposedly in the name of performance, but in reality all it did was antagonise users and publishers alike.

Core web vitals are an attempt to put numbers on user experience. This is always a tricky balancing act. You’ve got to watch out for the McNamara fallacy. Harry has already started noticing this:

A new and unusual phenomenon: clients reluctant (even refusing) to fix performance issues unless they directly improve Vitals.

Once you put a measurement on something, there’s a danger of focusing too much on the measurement. Chris is worried that we’re going to see tips’n’tricks for gaming core web vitals:

This feels like the start of a weird new era of web performance where the metrics of web performance have shifted to user-centric measurements, but people are implementing tricky strategies to game those numbers with methods that, if anything, slightly harm user experience.

The map is not the territory. The numbers are a proxy for user experience, but it’s notoriously difficult to measure intangible ideas like pain and frustration. As Laurie says:

This is 100% the downside of automatic tools that give you a “score”. It’s like gameification. It’s about hitting that perfect score instead of the holistic experience.

And Ethan has written about the power imbalance that exists when Google holds all the cards, whether it’s AMP or core web vitals:

Google used its dominant position in the marketplace to force widespread adoption of a largely proprietary technology for creating websites. By switching to Core Web Vitals, those power dynamics haven’t materially changed.

We would do well to remember:

When you measure, include the measurer.

But if we’re going to put numbers to user experience, the core web vitals are a pretty good spread of measurements: largest contentful paint, cumulative layout shift, and first input delay.

(If you prefer using initialisms, remember that CFP is Certified Financial Planner, CLS is Community Legal Services, and FID is Flame Ionization Detector. Together they form CWV, Catholic War Veterans.)

Of the web

I’m subscribed to a lot of blogs in my RSS reader. I follow some people because what they write about is very different to what I know about. But I also follow lots of people who have similar interests and ideas to me. So I’m not exactly in an echo chamber, but I do have the reverb turned up pretty high.

Sometimes these people post thoughts that are eerily similar to what I’ve been thinking about. Ethan has been known to do this. Get out of my head, Marcotte!

But even if Ethan wasn’t some sort of telepath, he’d still be in my RSS reader. We’re friends. Lots of the people in my RSS reader are my friends. When I read their words, I can hear their voices.

Then there are the people I’ve never met. Like Desirée García, Piper Haywood, or Jim Nielsen. Never met them, don’t know them, but damn, do I enjoy reading their blogs. Last year alone, I ended up linking to Jim’s posts ten different times.

Or Baldur Bjarnason. I can’t remember when I first came across his writing, but it really, really resonates with me. I probably owe him royalties for the amount of times I’ve cited his post Over-engineering is under-engineering.

His latest post is postively Marcottian in how it exposes what’s been fermenting in my own mind. But because he writes clearly, it really helps clarify my own thinking. It’s often been said that you should write to figure out what you think, and I can absolutely relate to that. But here’s a case where somebody else’s writing really helps to solidify my own thoughts.

Which type of novelty-seeking web developer are you?

It starts with some existentialist stock-taking. I can relate, what with the whole five decades thing. But then it turns the existential questioning to the World Wide Web itself, or rather, the people building the web.

In a way, it’s like taking the question of the great divide (front of the front end and back of the front end), and then turning it 45 degrees to reveal an entirely hidden dimension.

In examining the nature of the web, he hits on the litmus of how you view encapsulation:

I mention this first as it’s the aspect of the web that modern web developers hate the most without even giving it a label. Single-Page-Apps and GraphQL are both efforts to eradicate the encapsulation that’s baked into the foundation of every layer of the web.

Most modern devs are trying to get rid of it but it’s one of the web’s most strategic advantages.

I hadn’t thought of this before.

By default, if you don’t go against the grain of the web, each HTTP endpoint is encapsulated from each other.

Moreover, all of this can happen really fast if you aren’t going overboard with your CSS and JS.

He finishes with a look at another of the web’s most powerful features: distribution. In between are the things that make the web webby: hypertext and flexibility (The Dao of the Web).

It’s the idea that the web isn’t a single fixed thing but a fluid multitude whose shape is dictated by its surroundings.

This resonates with me because it highlights two different ways of viewing the web.

On the one hand, you can see the web purely as a distribution channel. In the past you might have been distributing a Flash movie. These days you might be distributing a single page app. Either way, the web is there as a low-friction way of getting your creation in front of other people.

The other way of building for the web is to go with the web’s grain, embracing flexibility and playing to the strengths of the medium through progressive enhancement. This is the distinction I was getting at when I talked about something being not just on the web, but of the web.

With that mindset, Baldur then takes us through some of the technologies that he’s excited about, like SvelteKit and Hotwire. I think it’s the same mindset that got me excited about service workers. As Baldur says:

They are helping the web become better at being its own thing.

That’s my tagline right there.

Principles and the English language

I work with words. Sometimes they’re my words. Sometimes they’re words that my colleagues have written:

One of my roles at Clearleft is “content buddy.” If anyone is writing a talk, or a blog post, or a proposal and they want an extra pair of eyes on it, I’m there to help.

I also work with web technologies, usually front-of-the-front-end stuff. HTML, CSS, and JavaScript. The technologies that users experience directly in web browsers.

I think a lot about design principles for the web. The two principles I keep coming back to are the robustness principle and the principle of least power.

When it comes to words, the guide that I return to again and again is George Orwell, specifically his short essay, Politics and the English Language.

Towards the end, he offers some rules for writing.

  1. Never use a metaphor, simile, or other figure of speech which you are used to seeing in print.
  2. Never use a long word where a short one will do.
  3. If it is possible to cut a word out, always cut it out.
  4. Never use the passive where you can use the active.
  5. Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent.
  6. Break any of these rules sooner than say anything outright barbarous.

These look a lot like design principles. Not only that, but some of them look like specific design principles. Take the robustness principle:

Be conservative in what you send, be liberal in what you accept.

That first part applies to Orwell’s third rule:

If it is possible to cut a word out, always cut it out.

Be conservative in what words you send.

Then there’s the principle of least power:

Choose the least powerful language suitable for a given purpose.

Compare that to Orwell’s second rule:

Never use a long word where a short one will do.

That could be rephrased as:

Choose the shortest word suitable for a given purpose.

Or, going in the other direction, the principle of least power could be rephrased in Orwell’s terms as:

Never use a powerful language where a simple language will do.

Oh, I like that! I like that a lot.

The principle of most availability

I’ve been thinking some more about the technical experience of booking a vaccination apointment and how much joy it brought me.

I’ve written before about how I’ve got a blind spot for the web so it’s no surprise that I was praising the use of a well marked-up form, styled clearly, and unencumbered by unnecessary JavaScript. But other technologies were in play too: Short Message Service (SMS) and email.

All of those technologies are platform-agnostic.

No matter what operating system I’m using, or what email software I’ve chosen, email works. It gets more complicated when you introduce HTML email. My response to that is the same as the old joke; you know the one: “Doctor, it hurts when I do this.” (“Well, don’t do that.”)

No matter what operating system my phone is using, SMS works. It gets more complicated when you introduce read receipts, memoji, or other additions. See my response to HTML email.

Then there’s the web. No matter what operating system I’m using on a device that could be a phone or a tablet or a laptop or desktop tower, and no matter what browser I’ve chosen to use, the World Wide Web works.

I originally said:

It feels like the principle of least power in action.

But another way of rephrasing “least power” is “most availability.” Technologies that are old, simple, and boring tend to be more widely available.

I remember when software used to come packaged in boxes and displayed on shelves. The packaging always had a list on the side. It looked like the nutritional information on a food product, but this was a list of “system requirements”: operating system, graphics card, sound card, CPU. I never liked the idea of system requirements. It felt so …exclusionary. And for me, the promise of technology was liberation and freedom to act on my own terms.

Hence my soft spot for the boring and basic technologies like email, SMS, and yes, web pages. The difference with web pages is that you can choose to layer added extras on top. As long as the fundamental functionality is using universally-supported technology, you’re free to enhance with all the latest CSS and JavaScript. If any of it fails, that’s okay: it falls back to a nice solid base.

Alas, many developers don’t build with this mindset. I mean, I understand why: it means thinking about users with the most boring, least powerful technology. It’s simpler and more exciting to assume that everyone’s got a shared baseline of newer technology. But by doing that, you’re missing out on one of the web’s superpowers: that something served up at the same URL with the same underlying code can simultaneously serve people with older technology and also provide a whizz-bang experience to people with the latest and greatest technology.

Anyway, I’ve been thinking about the kind of communication technologies that are as universal as email, SMS, and the web.

QR codes are kind of heading in that direction, although I still have qualms because of their proprietary history. But there’s something nice and lo-fi about them. They’re like print stylesheets in reverse (and I love print stylesheets). A funky little bridge between the physical and the digital. I just wish they weren’t so opaque: you never know if scanning that QR code will actually take you to the promised resource, or if you’re about to rickroll yourself.

Telephone numbers kind of fall into the same category as SMS, but with the added option of voice. I’ve always found the prospect of doing something with, say, Twilio’s API more interesting than building something inside a walled garden like Facebook Messenger or Alexa.

I know very little about chat apps or voice apps, but I don’t think there’s a cross-platform format that works with different products, right? I imagine it’s like the situation with native apps which require a different codebase for each app store and operating system. And so there’s a constant stream of technologies that try to fulfil the dream of writing once and running everywhere: React Native, Flutter.

They’re trying to solve a very clear and obvious problem: writing the same app more than once is really wasteful. But that’s the nature of the game when it comes to runtime-specific apps. The only alternative is to either deliberately limit your audience …or apply the principle of least power/most availability.

The wastefulness of having to write the same app for multiple platforms isn’t the only thing that puts me off making native apps. The exclusivity works in two directions. There’s the exclusive nature of the runtime that requires a bespoke codebase. There’s also the exclusive nature of the app store. It feels like a return to shelves of packaged software with strict system requirements. You can’t just walk in and put your software on the shelf. That’s the shopkeeper’s job.

There is no shopkeeper for the World Wide Web.

Service worker weirdness in Chrome

I think I’ve found some more strange service worker behaviour in Chrome.

It all started when I was checking out the very nice new redesign of WebPageTest. I figured while I was there, I’d run some of my sites through it. I passed in a URL from The Session. When the test finished, I noticed that the “screenshot” tab said that something was being logged to the console. That’s odd! And the file doing the logging was the service worker script.

I fired up Chrome (which isn’t my usual browser), and started navigating around The Session with dev tools open to see what appeared in the console. Sure enough, there was a failed fetch attempt being logged. The only time my service worker script logs anything is in the catch clause of fetching pages from the network. So Chrome was trying to fetch a web page, failing, and logging this error:

The service worker navigation preload request failed with a network error.

But all my pages were loading just fine. So where was the error coming from?

After a lot of spelunking and debugging, I think I’ve figured out what’s happening…

First of all, I’m making use of navigation preloads in my service worker. That’s all fine.

Secondly, the website is a progressive web app. It has a manifest file that specifies some metadata, including start_url. If someone adds the site to their home screen, this is the URL that will open.

Thirdly, Google recently announced that they’re tightening up the criteria for displaying install prompts for progressive web apps. If there’s no network connection, the site still needs to return a 200 OK response: either a cached copy of the URL or a custom offline page.

So here’s what I think is happening. When I navigate to a page on the site in Chrome, the service worker handles the navigation just fine. It also parses the manifest file I’ve linked to and checks to see if that start URL would load if there were no network connection. And that’s when the error gets logged.

I only noticed this behaviour because I had specified a query string on my start URL in the manifest file. Instead of a start_url value of /, I’ve set a start_url value of /?homescreen. And when the error shows up in the console, the URL being fetched is /?homescreen.

Crucially, I’m not seeing a warning in the console saying “Site cannot be installed: Page does not work offline.” So I think this is all fine. If I were actually offline, there would indeed be an error logged to the console and that start_url request would respond with my custom offline page. It’s just a bit confusing that the error is being logged when I’m online.

I thought I’d share this just in case anyone else is logging errors to the console in the catch clause of fetches and is seeing an error even when everything appears to be working fine. I think there’s nothing to worry about.

Update: Jake confirmed my diagnosis and agreed that the error is a bit confusing. The good news is that it’s changing. In Chrome Canary the error message has already been updated to:

DOMException: The service worker navigation preload request failed due to a network error. This may have been an actual network error, or caused by the browser simulating offline to see if the page works offline: see https://w3c.github.io/manifest/#installability-signals

Much better!

Good form

I got a text this morning at 9:40am. It was from the National Health Service, NHS. It said:

You are now eligible for your free NHS coronavirus vaccination. Please book online at https://www.nhs.uk/covid-vaccination or by calling 119. You will need to provide your name, date of birth and postcode. Your phone number has been obtained from your GP records.

Well, it looks like I timed turning fifty just right!

I typed that URL in on my laptop. It redirected to a somewhat longer URL. There’s a very clear call-to-action to “Book or manage your coronavirus vaccination.” On that page there’s very clear copy about who qualifies for vaccination. I clicked on the “Book my appointments” button.

From there, it’s a sequence of short forms, clearly labelled. Semantic accessible HTML, some CSS, and nothing more. If your browser doesn’t support JavaScript (or you’ve disabled it for privacy reasons), that won’t make any difference to your experience. This is the design system in action and it’s an absolute pleasure to experience.

I consider myself relatively tech-savvy so I’m probably not the best judge of the complexity of the booking system, but it certainly seemed to be as simple as possible (but no simpler). It feels like the principle of least power in action.

SMS to HTML (with a URL as the connective tissue between the two). And if those technologies aren’t available, there’s still a telephone number, and finally, a letter by post.

This experience reminded me of where the web really excels. It felt a bit like the web-driven outdoor dining I enjoyed last summer:

Telling people “You have to go to this website” …that seems reasonable. But telling people “You have to download this app” …that’s too much friction.

A native app would’ve been complete overkill. That may sound obvious, but it’s surprising how often the overkill option is the default.

Give me a URL—either by SMS or QR code or written down—and make sure that when I arrive at that URL, the barrier to entry is as low as possible.

Maybe I’ll never need to visit that URL again. In the case of the NHS, I hope I won’t need to visit again. I just need to get in, accomplish my task, and get out again. This is where the World Wide Web shines.

In five days time, I will get my first vaccine jab. I’m very thankful. Thank you to the NHS. Thank you to everyone who helped build the booking process. It’s beautiful.

When service workers met framesets

Oh boy, do I have some obscure browser behaviour for you!

To set the scene…

I’ve been writing here in my online journal for almost twenty years. The official anniversary will be on September 30th. But this website has been even online longer than that, just in a very different form.

Here’s the first version of adactio.com.

Like a tour guide taking you around the ruins of some lost ancient civilisation, let me point out some interesting features:

  • Observe the .shtml file extension. That means it was once using Apache’s server-side includes, a simple way of repeating chunks of markup across pages. Scientists have been trying to reproduce the wisdom of the ancients using modern technology ever since.
  • See how the layout is 100vw and 100vh? Well, this was long before viewport units existed. In fact there is no CSS at all on that page. It’s one big table element with 100% width and 100% height.
  • So if there’s no CSS, where is the border-radius coming from? Let me introduce you to an old friend—the non-animated GIF. It’s got just enough transparency (though not proper alpha transparency) to fake rounded corners between two solid colours.
  • The management takes no responsibility for any trauma that might befall you if you view source. There you will uncover JavaScript from the dawn of time; ancient runic writing like if (navigator.appName == "Netscape")

Now if your constitution was able to withstand that, brace yourself for what happens when you click on either of the two links, deutsch or english.

You find yourself inside a frameset. You may also experience some disorienting “DHTML”—the marketing term given to any combination of JavaScript and positioning in the late ’90s.

Note that these are not iframes, they are frames. Different thing. You could create single page apps long before Ajax was a twinkle in Jesse James Garrett’s eye.

If you view source, you’ll see a React-like component system. Each frameset component contains frame components that are isolated from one another. They’re like web components. Each frame has its own (non-shadow) DOM. That’s because each frame is actually a separate web page. If you right-click on any of the frames, your browser should give the option to view the framed document in its own tab or window.

Now for the part where modern and ancient technologies collide…

If you’re looking at the frameset URL in Firefox or Safari, everything displays as it should in all its ancient glory. But if you’re looking in Google Chrome and you’ve visited adactio.com before, something very odd happens.

Each frame of the frameset displays my custom offline page. The only way that could be served up is through my service worker script. You can verify this by opening the framest URL in an incognito window—everything works fine when no service worker has been registered.

I have no idea why this is happening. My service worker logic is saying “if there’s a request for a web page, try fetching it from the network, otherwise look in the cache, otherwise show an offline page.” But if those page requests are initiated by a frame element, it goes straight to showing the offline page.

Is this a bug? Or perhaps this is the correct behaviour for some security reason? I have no idea.

I wonder if anyone has ever come across this before. It’s a very strange combination of factors:

  • a domain served over HTTPS,
  • that registers a service worker,
  • but also uses framesets and frames.

I could submit a bug report about this but I fear I would be laughed out of the bug tracker.

Still …the World Wide Web is remarkable for its backward compatibility. This behaviour is unusual because browser makers are at pains to support existing content and never break the web.

Technically a modern website (one that registers a service worker) shouldn’t be using deprecated technology like frames. But browsers still need to be able support those old technologies in order to render old websites.

This situation has only arisen because the same domain—adactio.com—is host to a modern website and a really old one.

Maybe Chrome is behaving strangely because I’ve built my online home on ancient burial ground.

Update: Both Remy and Jake did some debugging and found the issue…

It’s all to do with navigation preloads and the value of event.preloadResponse, which I believe is only supported in Chrome which would explain the differences between browsers.

According to this post by Jake:

event.preloadResponse is a promise that resolves with a response, if:

  • Navigation preload is enabled.
  • The request is a GET request.
  • The request is a navigation request (which browsers generate when they’re loading pages, including iframes).

Otherwise event.preloadResponse is still there, but it resolves with undefined.

Notice that iframes are mentioned, but not frames.

My code was assuming that if event.preloadRepsonse exists in my block of code for responding to page requests, then there’d be a response. But if the request was initiated from a frameset, it is a request for a page and event.preloadRepsonse does exist …but it’s undefined.

I’ve updated my code now to check this assumption (and fall back to fetch).

This may technically still be a bug though. Shouldn’t a page loaded from a frameset count as a navigation request?

Design engineer

It’s been just over two years since Chris wrote his magnum opus about The Great Divide. It really resonated with me, and a lot of other people.

The crux of it is that the phrase “front-end development” has become so broad and applies to so many things, that it has effectively lost its usefulness:

Two front-end developers are sitting at a bar. They have nothing to talk about.

Brad nailed the differences in responsibilities when he described them as front-of-the-front-end and back-of-the-front-end web development:

A front-of-the-front-end developer is a web developer who specializes in writing HTML, CSS, and presentational JavaScript code.

A back-of-the-front-end developer is a web developer who specializes in writing JavaScript code necessary to make a web application function properly.

In my experience, the term “full stack developer” is often self-applied by back-of-the-front-end developers who perhaps underestimate the complexity of front-of-the-front development.

Me, I’m very much a front-of-the-front developer. And the dev work we do at Clearleft very much falls into that realm.

This division of roles and responsibilities reminds me of a decision we made in the founding days of Clearleft. Would we attempt to be a full-service agency, delivering everything from design to launch? Or would we specialise? We decided to specialise, doubling down on UX design, which was at the time an under-served area. But we still decided to do front-end development. We felt that working with the materials of the web would allow us to deliver better UX.

We made a conscious decision not to do back-end development. Partly it was a question of scale. If you were a back-end shop, you probably had to double down on one stack: PHP or Ruby or Python. We didn’t want to have to turn away any clients based on their tech stack. Of course this meant that we had to partner with other agencies that specialised in those stacks, and that’s what we did—we had trusted partners for Drupal development, Rails development, Wordpress development, and so on.

The world of front-end development didn’t have that kind of fragmentation. The only real split at the time was between Flash agencies and web standards (HTML, CSS, and JavaScript).

Overall, our decision to avoid back-end development stood us in good stead. There were plenty of challenges though. We had to learn how to avoid “throwing stuff over the wall” at whoever would be doing the final back-end implementation. I think that’s why we latched on to design systems so early. It was clearly a better deliverable for the people building the final site—much better than mock-ups or pages.

Avoiding back-end development meant we also avoided long-term lock-in with maintainence, security, hosting, and so on. It might sound strange for an agency to actively avoid long-term revenue streams, but at Clearleft it’s always been our philosophy to make ourselves redundant. We want to give our clients everything they need—both in terms of deliverables and knowledge—so that they aren’t dependent on us.

That all worked great as long as there was a clear distinction between front-end development and back-end development. Front-end development was anything that happened in a browser. Back-end development was anything that happened on the server.

But as the waters muddied and complex business logic migrated from the server to the client, our offering became harder to clarify. We’d tell clients that we did front-end development (meaning we’d supply them with components formed of HTML, CSS, and JavaScript) and they might expect us to write application logic in React.

That’s why Brad’s framing resonated with me. Clearleft does front-of-front-end development, but we liaise with our clients’ back-of-the-front-end developers. In fact, that bridging work—between design and implementation—is where devs at Clearleft shine.

As much as I can relate to the term front-of-front-end, it doesn’t exactly roll off the tongue. I don’t expect it to be anyone’s job title anytime soon.

That’s why I was so excited by the term “design engineer,” which I think I first heard from Natalya Shelburne. There’s even a book about it and the job description sounds very much like the front-of-the-front-end work but with a heavy emphasis on the collaboration and translation between design and implementation. As Trys puts it:

What I love about the name “Design Engineer”, is that it’s entirely focused on the handshake between those two other roles.

There’s no mention of UI, CSS, front-end, design systems, documentation, prototyping, tooling or any ‘hard’ skills that could be used in the role itself.

Trys has been doing some soul-searching and has come to the conclusion “I think I might be a design engineer…”. He has also written on the Clearleft blog about how well the term describes design and development at Clearleft.

Personally, I’m not a fan of using the term “engineer” to refer to anyone who isn’t actually a qualified engineer—I explain why in my talk Building—but I accept that that particular ship has sailed. And the term “design developer” just sounds odd. So I’m all in using the term “design engineer”.

I can imagine this phrase being used in a job ad. It could also be attached to levels: a junior design engineer, a mid-level design engineer, a senior design engineer; each level having different mixes of code and collaboration (maybe a head of design enginering never writes any code).

Trys has written a whole series of posts on the nitty-gritty work involved in design engineering. I highly recommend reading all of them:

Authentication

Two-factor authentication is generally considered A Good Thing™️ when you’re logging in to some online service.

The word “factor” here basically means “kind” so you’re doing two kinds of authentication. Typical factors are:

  • Something you know (like a password),
  • Something you have (like a phone or a USB key),
  • Something you are (biometric Black Mirror shit).

Asking for a password and an email address isn’t two-factor authentication. They’re two pieces of identification, but they’re the same kind (something you know). Same goes for supplying your fingerprint and your face: two pieces of information, but of the same kind (something you are).

None of these kinds of authentication are foolproof. All of them can change. All of them can be spoofed. But when you combine factors, it gets a lot harder for an attacker to breach both kinds of authentication.

The most common kind of authentication on the web is password-based (something you know). When a second factor is added, it’s often connected to your phone (something you have).

Every security bod I’ve talked to recommends using an authenticator app for this if that option is available. Otherwise there’s SMS—short message service, or text message to most folks—but SMS has a weakness. Because it’s tied to a phone number, technically you’re only proving that you have access to a SIM (subscriber identity module), not a specific phone. In the US in particular, it’s all too easy for an attacker to use social engineering to get a number transferred to a different SIM card.

Still, authenticating with SMS is an option as a second factor of authentication. When you first sign up to a service, as well as providing the first-factor details (a password and a username or email address), you also verify your phone number. Then when you subsequently attempt to log in, you input your password and on the next screen you’re told to input a string that’s been sent by text message to your phone number (I say “string” but it’s usually a string of numbers).

There’s an inevitable friction for the user here. But then, there’s a fundamental tension between security and user experience.

In the world of security, vigilance is the watchword. Users need to be aware of their surroundings. Is this web page being served from the right domain? Is this email coming from the right address? Friction is an ally.

But in the world of user experience, the opposite is true. “Don’t make me think” is the rallying cry. Friction is an enemy.

With SMS authentication, the user has to manually copy the numbers from the text message (received in a messaging app) into a form on a website (in a different app—a web browser). But if the messaging app and the browser are on the same device, it’s possible to improve the user experience without sacrificing security.

If you’re building a form that accepts a passcode sent via SMS, you can use the autocomplete attribute with a value of “one-time-code”. For a six-digit passcode, your input element might look something like this:

<input type="text" maxlength="6" inputmode="numeric" autocomplete="one-time-code">

With one small addition to one HTML element, you’ve saved users some tedious drudgery.

There’s one more thing you can do to improve security, but it’s not something you add to the HTML. It’s something you add to the text message itself.

Let’s say your website is example.com and the text message you send reads:

Your one-time passcode is 123456.

Add this to the end of the text message:

@example.com #123456

So the full message reads:

Your one-time passcode is 123456.

@example.com #123456

The first line is for humans. The second line is for machines. Using the @ symbol, you’re telling the device to only pre-fill the passcode for URLs on the domain example.com. Using the # symbol, you’re telling the device the value of the passcode. Combine this with autocomplete="one-time-code" in your form and the user shouldn’t have to lift a finger.

I’m fascinated by these kind of emergent conventions in text messages. Remember that the @ symbol and # symbol in Twitter messages weren’t ideas from Twitter—they were conventions that users started and the service then adopted.

It’s a bit different with the one-time code convention as there is a specification brewing from representatives of both Google and Apple.

Tess is leading from the Apple side and she’s got another iron in the fire to make security and user experience play nicely together using the convention of the /.well-known directory on web servers.

You can add a URL for /.well-known/change-password which redirects to the form a user would use to update their password. Browsers and password managers can then use this information if they need to prompt a user to update their password after a breach. I’ve added this to The Session.

Oh, and on that page where users can update their password, the autocomplete attribute is your friend again:

<input type="password" autocomplete="new-password">

If you want them to enter their current password first, use this:

<input type="password" autocomplete="current-password">

All of the things I’ve mentioned—the autocomplete attribute, origin-bound one-time codes in text messages, and a well-known URL for changing passwords—have good browser support. But even if they were only supported in one browser, they’d still be worth adding. These additions do absolutely no harm to browsers that don’t yet support them. That’s progressive enhancement.