Tags: fix



Monday, October 19th, 2020

Continuous partial browser support

Vendor prefixes didn’t work. The theory was sound. It was a way of marking CSS and JavaScript features as being experimental. Developers could use the prefixed properties as long as they understood that those features weren’t to be relied upon.

That’s not what happened though. Developers used vendor-prefixed properties as though they were stable. Tutorials were published that basically said “Go ahead and use these vendor-prefixed properties and ship it!” There were even tools that would add the prefixes for you so you didn’t have to type them out for yourself.

Browsers weren’t completely blameless either. Long after features were standardised, they would only be supported in their prefixed form. Apple was and is the worst for this. To this day, if you want to use the clip-path property in your CSS, you’ll need to duplicate your declaration with -webkit-clip-path if you want to support Safari. It’s been like that for seven years and counting.

Like capitalism, vendor prefixes were one of those ideas that sounded great in theory but ended up being unworkable in practice.

Still, developers need some way to get their hands on experiment features. But we don’t want browsers to ship experimental features without some kind of safety mechanism.

The current thinking involves something called origin trials. Here’s the explainer from Microsoft Edge and here’s Google Chrome’s explainer:

  • Developers are able to register for an experimental feature to be enabled on their origin for a fixed period of time measured in months. In exchange, they provide us their email address and agree to give feedback once the experiment ends.
  • Usage of these experiments is constrained to remain below Chrome’s deprecation threshold (< 0.5% of all Chrome page loads) by a system which automatically disables the experiment on all origins if this threshold is exceeded.

I think it works pretty well. If you’re really interested in kicking the tyres on an experimental feature, you can opt in to the origin trial. But it’s very clear that you wouldn’t want to ship it to production.

That said…

You could ship something that’s behind an origin trial, but you’d have to make sure you’re putting safeguards in place. At the very least, you’d need to do feature detection. You certainly couldn’t use an experimental feature for anything mission critical …but you could use it as an enhancement.

And that is a pretty great way to think about all web features, experimental or otherwise. Don’t assume the feature will be supported. Use feature detection (or @supports in the case of CSS). Try to use the feature as an enhancement rather than a dependency.

If you treat all browser features as though they’re behind an origin trial, then suddenly the landscape of browser support becomes more navigable. Instead of looking at the support table for something on caniuse.com and thinking, “I wish more browsers supported this feature so that I could use it!”, you can instead think “I’m going to use this feature today, but treat it as an experimental feature.”

You can also do it for well-established features like querySelector, addEventListener, and geolocation. Instead of assuming that browser support is universal, it doesn’t hurt to take a more defensive approach. Assume nothing. Acknowledge and embrace unpredictability.

The debacle with vendor prefixes shows what happens if we treat experimental features as though they’re stable. So let’s flip that around. Let’s treat stable features as though they’re experimental. If you cultivate that mindset, your websites will be more robust and resilient.

Friday, February 28th, 2020

Fixed Headers and Jump Links? The Solution is scroll-margin-top | CSS-Tricks

I didn’t know about scroll-margin-top! I wonder if you could apply a universal rule …like, say you’ve got a fixed header that’s 2em in height, couldn’t you declare:

:target { scroll-margin-top: 2em; }

Tuesday, July 2nd, 2019

The trimCache function in Going Offline …again

It seems that some code that I wrote in Going Offline is haunted. It’s the trimCache function.

First, there was the issue of a typo. Or maybe it’s more of a brainfart than a typo, but either way, there’s a mistake in the syntax that was published in the book.

Now it turns out that there’s also a problem with my logic.

To recap, this is a function that takes two arguments: the name of a cache, and the maximum number of items that cache should hold.

function trimCache(cacheName, maxItems) {

First, we open up the cache:

.then( cache => {

Then, we get the items (keys) in that cache:

.then(keys => {

Now we compare the number of items (keys.length) to the maximum number of items allowed:

if (keys.length > maxItems) {

If there are too many items, delete the first item in the cache—that should be the oldest item:


And then run the function again:

    trimCache(cacheName, maxItems)

A-ha! See the problem?

Neither did I.

It turns out that, even though I’m using then, the function will be invoked immediately, instead of waiting until the first item has been deleted.

Trys helped me understand what was going on by making a useful analogy. You know when you use setTimeout, you can’t put a function—complete with parentheses—as the first argument?

window.setTimeout(doSomething(someValue), 1000);

In that example, doSomething(someValue) will be invoked immediately—not after 1000 milliseconds. Instead, you need to create an anonymous function like this:

window.setTimeout( function() {
}, 1000);

Well, it’s the same in my trimCache function. Instead of this:

    trimCache(cacheName, maxItems)

I need to do this:

.then( function() {
    trimCache(cacheName, maxItems)

Or, if you prefer the more modern arrow function syntax:

.then( () => {
    trimCache(cacheName, maxItems)

Either way, I have to wrap the recursive function call in an anonymous function.

Here’s a gist with the updated trimCache function.

What’s annoying is that this mistake wasn’t throwing an error. Instead, it was causing a performance problem. I’m using this pattern right here on my own site, and whenever my cache of pages or images gets too big, the trimCaches function would get called …and then wouldn’t stop running.

I’m very glad that—witht the help of Trys at last week’s Homebrew Website Club Brighton—I was finally able to get to the bottom of this. If you’re using the trimCache function in your service worker, please update the code accordingly.

Management regrets the error.

Monday, January 7th, 2019

Angular, Autoprefixer, IE11, and CSS Grid Walk into a Bar… - daverupert.com

Dave on the opaqueness of toolchains:

As toolchains grow and become more complex, unless you are expertly familiar with them, it’s very unclear what transformations are happening in our code. Tracking the differences between the input and output and the processes that code underwent can be overwhelming. When there’s a problem, it’s increasingly difficult to hop into the assembly line and diagnose the issue.

There’s a connection here to one of the biggest issues with what’s currently being labelled “AI”:

In the same way AI needs some design to show its work in how it came to its final answer, I feel that our automated build tools could use some help as well.

I really like this suggestion for making the invisble visible:

I sometimes wonder if Webpack or Gulp or [Insert Your Build Tool Here] could benefit from a Scratch-like interface for buildchains.

Tuesday, September 25th, 2018

The State of Fieldset Interoperability - Bocoup

The long-standing difficulties of styling fieldset and legend are finally getting addressed …although I’m a little shocked that the solution involves extending -webkit-appearance. I think that, at this point, we should be trying to get rid of vendor prefixes from the web once and for all, not adding to them. Still, needs must, I suppose.

Tuesday, July 17th, 2018

Should I try to use the IE version of Grid Layout? Revisited for 2018

Rachel follows up on my recent post about CSS grid in old IE with her thoughts.

As Jeremy notes, the usefulness of a tool like Autoprefixer is diminishing, which is a good thing. It is becoming far easier to code in a way that supports all browsers, where support means usable in an appropriate way for the technology the user has in front of them. Embrace that, and be glad for the fact that we can reduce complexity based on the increasing interoperability of CSS in our browsers.

Friday, July 13th, 2018

CSS grid in Internet Explorer 11

When I was in Boston, speaking on a lunchtime panel with Rachel at An Event Apart, we took some questions from the audience about CSS grid. Inevitably, a question about browser support came up—specifically about support in Internet Explorer 11.

(Technically, you can use CSS grid in IE11—in fact it was the first browser to ship a version of grid—but the prefixed syntax is different to the standard and certain features are missing.)

Rachel gave a great balanced response, saying that you need to look at your site’s stats to determine whether it’s worth the investment of your time trying to make a grid work in IE11.

My response was blunter. I said I just don’t consider IE11 as a browser that supports grid.

Now, that might sound harsh, but what I meant was: you’re already dividing your visitors into browsers that support grid, and browsers that don’t …and you’re giving something to those browsers that don’t support grid. So I’m suggesting that IE11 falls into that category and should receive the layout you’re giving to browsers that don’t support grid …because really, IE11 doesn’t support grid: that’s the whole reason why the syntax is namespaced by -ms.

You could jump through hoops to try to get your grid layout working in IE11, as detailed in a three-part series on CSS Tricks, but at that point, the amount of effort you’re putting in negates the time-saving benefits of using CSS grid in the first place.

Frankly, the whole point of prefixed CSS is that is not used after a reasonable amount of time (originally, the idea was that it would not be used in production, but that didn’t last long). As we’ve moved away from prefixes to flags in browsers, I’m seeing the amount of prefixed properties dropping, and that’s very, very good. I’ve stopped using autoprefixer on new projects, and I’ve been able to remove it from some existing ones—please consider doing the same.

And when it comes to IE11, I’ll continue to categorise it as a browser that doesn’t support CSS grid. That doesn’t mean I’m abandoning users of IE11—far from it. It means I’m giving them the layout that’s appropriate for the browser they’re using.

Remember, websites do not need to look exactly the same in every browser.

Thursday, July 5th, 2018

The trimCache function in Going Offline

Paul Yabsley wrote to let me know about an error in Going Offline. It’s rather embarrassing because it’s code that I’m using in the service worker for adactio.com but for some reason I messed it up in the book.

It’s the trimCache function in Chapter 7: Tidying Up. That’s the reusable piece of code that recursively reduces the number of items in a specified cache (cacheName) to a specified amount (maxItems). On page 95 and 96 I describe the process of creating the function which, in the book, ends up like this:

 function trimCache(cacheName, maxItems) {
   cacheName.open( cache => {
     .then( items => {
       if (items.length > maxItems) {
           trimCache(cacheName, maxItems)
         ); // end delete then
       } // end if
     }); // end keys then
   }); // end open
 } // end function

See the problem? It’s right there at the start when I try to open the cache like this:

cacheName.open( cache => {

That won’t work. The open method only works on the caches object—I should be passing the name of the cache into the caches.open method. So the code should look like this:

caches.open( cacheName )
.then( cache => {

Everything else remains the same. The corrected trimCache function is here:

function trimCache(cacheName, maxItems) {
  .then( cache => {
    .then(items => {
      if (items.length > maxItems) {
          trimCache(cacheName, maxItems)
        ); // end delete then
      } // end if
    }); // end keys then
  }); // end open then
} // end function

Sorry about that! I must’ve had some kind of brainfart when I was writing (and describing) that one line of code.

You may want to deface your copy of Going Offline by taking a pen to that code example. Normally I consider the practice of writing in books to be barbarism, but in this case …go for it.

Update: There was another error in the code for trimCache! Here’s the fix.

Sunday, June 3rd, 2018


I’ve come to believe that the goal of any good framework should be to make itself unnecessary.

Brian said it explicitly of his PhoneGap project:

The ultimate purpose of PhoneGap is to cease to exist.

That makes total sense, especially if your code is a polyfill—those solutions are temporary by design. Autoprefixer is another good example of a piece of code that becomes less and less necessary over time.

But I think it’s equally true of any successful framework or library. If the framework becomes popular enough, it will inevitably end up influencing the standards process, thereby becoming dispensible.

jQuery is the classic example of this. There’s very little reason to use jQuery these days because you can accomplish so much with browser-native JavaScript. But the reason why you can accomplish so much without jQuery is because of jQuery. I don’t think we would have querySelector without jQuery. The library proved the need for the feature. The same is true for a whole load of DOM scripting features.

The same process is almost certain to occur with React—it’s a good bet there will be a standardised equivalent to the virtual DOM at some point.

When Google first unveiled AMP, its intentions weren’t clear to me. I hoped that it existed purely to make itself redundant:

As well as publishers creating AMP versions of their pages in order to appease Google, perhaps they will start to ask “Why can’t our regular pages be this fast?” By showing that there is life beyond big bloated invasive web pages, perhaps the AMP project will work as a demo of what the whole web could be.

Alas, as time has passed, that hope shows no signs of being fulfilled. If anything, I’ve noticed publishers using the existence of their AMP pages as a justification for just letting their “regular” pages put on weight.

Worse yet, the messaging from Google around AMP has shifted. Instead of pitching it as a format for creating parallel versions of your web pages, they’re now also extolling the virtues of having your AMP pages be the only version you publish:

In fact, AMP’s evolution has made it a viable solution to build entire websites.

On an episode of the Dev Mode podcast a while back, AMP was a hotly-debated topic. But even those defending AMP were doing so on the understanding that it was more a proof-of-concept than a long-term solution (and also that AMP is just for news stories—something else that Google are keen to change).

But now it’s clear that the Google AMP Project is being marketed more like a framework for the future: a collection of web components that prioritise performance …which is kind of odd, because that’s also what Google’s Polymer project is. The difference being that pages made with Polymer don’t get preferential treatment in Google’s search results. I can’t help but wonder how the Polymer team feels about AMP’s gradual pivot onto their territory.

If the AMP project existed in order to create a web where AMP was no longer needed, I think I could get behind it. But the more it’s positioned as the only viable solution to solving performance, the more uncomfortable I am with it.

Which, by the way, brings me to one of the most pernicious ideas around Google AMP—positioning anyone opposed to it as not caring about web performance. Nothing could be further from the truth. It’s precisely because performance on the web is so important that it deserves a long-term solution, co-created by all of us: not some commandents delivered to us from on-high by one organisation, enforced by preferential treatment by that organisation’s monopoly in search.

It’s the classic logical fallacy:

  1. Performance! Something must be done!
  2. AMP is something.
  3. Now something has been done.

By marketing itself as the only viable solution to the web performance problem, I think the AMP project is doing itself a great disservice. If it positioned itself as an example to be emulated, I would welcome it.

I wish that AMP were being marketed more like a temporary polyfill. And as with any polyfill, I look forward to the day when AMP is no longer necesssary.

I want AMP to become extinct. I genuinely think that the Google AMP team should share that wish.

Tuesday, April 3rd, 2018

Everything You Know About Web Design Just Changed by Jen Simmons

Alright! It’s time for the final talk of the day at An Event Apart Seattle (Special Edition). Jen is wrapping up a CSStastic afternoon with her talk Everything You Know About Web Design Just Changed. These are my notes…

Ready for another hour of layout in CSS? Well, Jen will be showing no code in this talk. She’s actually nervous about this particular talk. Is she really planning to say “Everything about web design just changed”? That sounds so clickbaity! But she really believes we’re at an inflection point. This may be the sixth such point in the history of the web. One of those points where everything changes and we swap out our techniques.

For the last few years, we’ve been saying that everything changed when mobile came along. But actually, the real fight has been going on for longer than that. It’s the battle between wanting art and dealing with how the web works.

There’s a seminal book called Creating Killer Websites by David Siegel from 1996. In it, he describes the first time he saw the same site in two different browsers. His reaction was panic. The web gave control to the user. David Siegel wanted more control. And that’s how we got spacer gifs and tables for layout.

What are the five major changes in the history of web design?

  1. Simple HTML. There was only one kind of layout: flow layout. There’s no CSS, but the browser is still thinking of everything has having a box. Text takes up as much space as it needs. Images take up as much space as their size. This is flow. There wasn’t much you could do until tables came along. They were created for tabular content but abused for layouts. The “We need art!” crowd used what was available to them at the time. Lots of slicing and dicing.
  2. Flash. It was hard to get HTML tables to work in multiple browsers. Flash seemed like an amazing chance to start over. And we could do things that were previously only possible in CD-ROMs. As a designer, you take an element and place it where you want to go on the stage (the UI tradition that goes all the way back to Xerox PARC). We made some crazy sites, explored a lot of possibilities, and got a lot of control. But the downside was the lack of accessibility. We went back to getting to grips with the web as its own medium. Jeffrey’s book, Designing With Web Standards, was a rallying cry to allow HTML to return to doing what it was meant to.
  3. Fluid Layouts. This was a return to the way the web always behaved—content takes up as much room as it needs to. But this time there’s a certain amount of control over how things are laid out. Still, we pretended that nobody has screens smaller than 640 pixels or bigger than 1024 pixels. We still live with the idea of fluid columns today.
  4. Fixed-Width Layouts. The “We need art!” crowd wanted more control than fluid layouts offered. We pretended that everyone’s screen was at least 640 pixels, or later 800 pixels, or later 1024 pixels.
  5. Responsive Web Design. Unveiled by Ethan at An Event Apart Seattle in 2011: flexible grid; flexible images; media queries. It’s a return to fluid layouts, but the addition of media queries gives us more control. The idea of fluid image was a bit radical. Up until that point, we thought of images as always being their intrinsic size. But something Ethan said that day was “It’s not just about layout.” And it’s true. For the last eight years, it’s been about more than layout. You set out to redesign your website and end up redesigning your whole business. Responsive web design is, frankly, what the web is now.

But let’s talk about layout. What’s next? Intrinsic Web Design.

Why a new name? Why bother? Well, it was helpful to debate fluid vs. fixed, or table-based layouts: having words really helps. Over the past few years, Jen has needed a term for “responsive web design +”.

Responsive web design has flexible images. Intrinsic web design has flexible images …or fixed images. Whichever you want.

Responsive web design has a fluid columns. Intrinsic web design has fluid columns and rows.

Responsive web design uses media queries. Intrinsic web design doesn’t necessarily need them.

The name comes from words that have been floating in the ether. In Rachel’s talk, the words “sizing” and “intrinsic” came up a lot. This is about the nature of the web.

Let’s look at images specifically. Before responsive web design, images overflow their container if they are bigger than the container. Fluid images (as used in responsive web design) shrink and grow depending on the size of their container. You can also make images fluid in a vertical direction. If we make the image fluid vertically and horizontally, the image looks distorted. But now if we use object-fit: cover we can specify how we want the image to react.

Fixed or fluid? With grid layout, you can mix fixed and fluid. You can make a layout fluid until it hits a minimum size, at which point it stays fixed.

There are four stages of squishiness:

  1. fixed
  2. fr units (fluid)
  3. minmax()(fluid until fixed)
  4. auto (a return to flow)

That’s a powerful set of tools that may take us years to explore.

We can do truly two-dimensional layouts: rows and columns. Every one of those four stages of squishiness works for rows as well as columns. This means we can create intentional white space. Jen made a video about this and got the response that this was always possible, but it’s different now: it’s more intentional. You can set heights and widths.

We can have nested contexts now:

  1. Flow
  2. Flexbox (formatting context)
  3. Grid (formatting context)
  4. Multicolumn (formatting context)

Floats never created a new formatting context, which is why used clearfix. Now we don’t need hacks. You can mix and match, choosing the best layout tool for the job at hand. You can have a grid layout that has flexbox items within it. The Firefox dev tools allow you to inspect each layout type separately. You can use the nightly build to get the latest tools.

Then we’ve got ways to contract and expand content. We have more options now. For a while, we’ve had the option to squish and grow (e.g. with fluid images). Another is wrapping and reflowing (like we can do with text). Another option now is to add and remove whitespace. Maybe the content size doesn’t need to change; the whitespace shrinks and grows instead. An even more radical option now is to have things slide behind one another and overlap deliberately.

Sometimes you don’t even need to use media queries (meaning we’ve effectively got container queries). But we can still use media queries, as needed, to tweak the details.

So intrinsic web design is:

  1. Fluid and fixed
  2. Stages of squishiness
  3. Truly two-dimensional layouts
  4. Nested contexts
  5. Expand and contract content
  6. Media queries, as needed

We have a whole new sandbox that we can play in. You can find examples at labs.jensimmons.com.

See also:

Tuesday, February 27th, 2018

Moving Slowly and Fixing Things / Paul Robert Lloyd

Although design gets conflated with creation, its the act of improving what already exists — organising a room, editing a text, refining an interface, refactoring a codebase — that I enjoy the most.

Thursday, February 15th, 2018

Progressive Web App for FixMyStreet · Issue #1996 · mysociety/fixmystreet

Here’s a Github issue that turned into a good philosophical debate on how to build a progressive web app: should you enhance your existing site or creating a separate URL?

(For the record: I’m in favour of enhancing.)

Thursday, February 8th, 2018

Progressive enhancement and the things that are here to stay, with Jeremy Keith | Fixate

I enjoyed chatting to Larry Botha on the Fixate On Code podcast—I hope you’ll enjoy hearing it.

Available for your huffduffing pleasure.

Sunday, July 2nd, 2017

Sticky headers

A three-part series by Remy looking at one interface pattern (a sticky header) and how his code evolved and changed:

  1. Sticky headers
  2. Smooth scroll & sticky navigation
  3. CSS sticky nav & smooth scroll

Monday, September 12th, 2016

Oh, shit, git!

Bookmark this page! Who knew that so much knowledge could be condensed into one document? In this case, it’s life-saving git commands, explained in a user-centred way.

So here are some bad situations I’ve gotten myself into, and how I eventually got myself out of them in plain english.

Tuesday, April 26th, 2016

Updating Our Prefixing Policy | WebKit

Ted has snuck a blog post out from behind Apple’s wall of silence, and it’s good news: WebKit is not going to use vendor prefixes for new features.

Saturday, December 19th, 2015

Photo upload and progressive enhancement for FixMyStreet / mySociety

Matthew describes a very nice bit of progressive enhancement for drag’n’drop file uploads (similar to the CSS Tricks article I linked to recently).

It uses the Dropzone JS which looks like it aligns nicely with the progressive enhancement approach.

Tuesday, August 25th, 2015

Doing Science On The Web – Infrequently Noted

Alex recounts the sordid history of vendor prefixes and looks to new ways of allowing browsers to ship experimental features without causing long-term harm.

Monday, August 4th, 2014

The Mobile Web should just work for everyone - IEBlog

One more reason why you should never sniff user-agent strings: Internet Explorer is going to lie some more. Can’t really blame them though—if developers didn’t insist on making spurious conclusions based on information in the user-agent string, then browsers wouldn’t have to lie.

Oh, and Internet Explorer is going to parse -webkit prefixed styles. Again, if developers hadn’t abused vendor prefixes, we wouldn’t be in this mess.

Wednesday, April 23rd, 2014


I like this idea. It would be nice to see it catch on…

  1. Report a bug for any website or browser.
  2. Our team of volunteers diagnoses the bug.
  3. We send a fix to the site owner or browser.