Tags: html

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Wednesday, September 16th, 2020

A polyfill for button type=”share”

After writing about a declarative Web Share API here yesterday I thought I’d better share the idea (see what I did there?).

I opened an issue on the Github repo for the spec.

(I hope that’s the right place for this proposal. I know that in the past ideas were kicked around on the Discourse site for Web platform Incubator Community Group but I can’t stand Discourse. It literally requires JavaScript to render anything to the screen even though the entire content is text. If it turns out that that is the place I should’ve posted, I guess I’ll hold my nose and do it using the most over-engineered reinvention of the browser I’ve ever seen. But I believe that the plan is for WICG to migrate proposals to Github anyway.)

I also realised that, as the JavaScript Web Share API already exists, I can use it to polyfill my suggestion for:

<button type="share">

The polyfill also demonstrates how feature detection could work. Here’s the code.

This polyfill takes an Inception approach to feature detection. There are three nested levels:

  1. This browser supports button type="share". Great! Don’t do anything. Otherwise proceed to level two.
  2. This browser supports the JavaScript Web Share API. Use that API to share the current page URL and title. Otherwise proceed to level three.
  3. Use a mailto: link to prefill an email with the page title as the subject and the URL in the body. Ya basic!

The idea is that, as long as you include the 20 lines of polyfill code, you could start using button type="share" in your pages today.

I’ve made a test page on Codepen. I’m just using plain text in the button but you could use a nice image or SVG or combination. You can use the Codepen test page to observe two of the three possible behaviours browsers could exhibit:

  1. A browser supports button type="share". Currently that’s none because I literally made this shit up yesterday.
  2. A browser supports the JavaScript Web Share API. This is Safari on Mac, Edge on Windows, Safari on iOS, and Chrome, Samsung Internet, and Firefox on Android.
  3. A browser supports neither button type="share" nor the existing JavaScript Web Share API. This is Firefox and Chrome on desktop (and Edge if you’re on a Mac).

See the Pen Polyfill for button type=”share" by Jeremy Keith (@adactio) on CodePen.

The polyfill doesn’t support Internet Explorer 11 or lower because it uses the DOM closest() method. Feel free to fork and rewrite if you need to support old IE.

Tuesday, September 15th, 2020

A declarative Web Share API

I’ve written about the Web Share API before. It’s a handy little bit of JavaScript that—if supported—brings up a system-level way of sharing a page. Seeing as it probably won’t be long before we won’t be able to see full URLs in browsers anymore, it’s going to fall on us as site owners to provide this kind of fundamental access.

Right now the Web Share API exists entirely in JavaScript. There are quite a few browser APIs like that, and it always feels like a bit of a shame to me. Ideally there should be a JavaScript API and a declarative option, even if the declarative option isn’t as powerful.

Take form validation. To cover the most common use cases, you probably only need to use declarative markup like input type="email" or the required attribute. But if your use case gets a bit more complicated, you can reach for the Constraint Validation API in JavaScript.

I like that pattern. I wish it were an option for JavaScript-only APIs. Take the Geolocation API, for example. Right now it’s only available through JavaScript. But what if there were an input type="geolocation" ? It wouldn’t cover all use cases, but it wouldn’t have to. For the simple case of getting someone’s location (like getting someone’s email or telephone number), it would do. For anything more complex than that, that’s what the JavaScript API is for.

I was reminded of this recently when Ada Rose Cannon tweeted:

It really feels like there should be a semantic version of the share API, like a mailto: link

I think she’s absolutely right. The Web Share API has one primary use case: let the user share the current page. If that use case could be met in a declarative way, then it would have a lower barrier to entry. And for anyone who needs to do something more complicated, that’s what the JavaScript API is for.

But Pete LePage asked:

How would you feature detect for it?

Good question. With the JavaScript API you can do feature detection—if the API isn’t supported you can either bail or provide your own implementation.

There a few different ways of extending HTML that allow you to provide a fallback for non-supporting browsers.

You could mint a new element with a content model that says “Browsers, if you do support this element, ignore everything inside the opening and closing tags.” That’s the way that the canvas element works. It’s the same for audio and video—they ignore everything inside them that isn’t a source element. So developers can provide a fallback within the opening and closing tags.

But forging a new element would be overkill for something like the Web Share API (or Geolocation). There are more subtle ways of extending HTML that I’ve already alluded to.

Making a new element is a lot of work. Making a new attribute could also be a lot of work. But making a new attribute value might hit the sweet spot. That’s why I suggested something like input type="geolocation" for the declarative version of the Geolocation API. There’s prior art here; this is how we got input types for email, url, tel, color, date, etc. The key piece of behaviour is that non-supporting browsers will treat any value they don’t understand as “text”.

I don’t think there should be input type="share". The action of sharing isn’t an input. But I do think we could find an existing HTML element with an attribute that currently accepts a list of possible values. Adding one more value to that list feels like an inexpensive move.

Here’s what I suggested:

<button type=”share” value=”title,text”>

For non-supporting browsers, it’s a regular button and needs polyfilling, no different to the situation with the JavaScript API. But if supported, no JS needed?

The type attribute of the button element currently accepts three possible values: “submit”, “reset”, or “button”. If you give it any other value, it will behave as though you gave it a type of “submit” or “button” (depending on whether it’s in a form or not) …just like an unknown type value on an input element will behave like “text”.

If a browser supports button type="share”, then when the user clicks on it, the browser can go “Right, I’m handing over to the operating system now.”

There’s still the question of how to pass data to the operating system on what gets shared. Currently the JavaScript API allows you to share any combination of URL, text, and description.

Initially I was thinking that the value attribute could be used to store this data in some kind of key/value pairing, but the more I think about it, the more I think that this aspect should remain the exclusive domain of the JavaScript API. The declarative version could grab the current URL and the value of the page’s title element and pass those along to the operating system. If you need anything more complex than that, use the JavaScript API.

So what I’m proposing is:

<button type="share">

That’s it.

But how would you test for browser support? The same way as you can currently test for supported input types. Make use of the fact that an element’s attribute value and an element’s property value (which 99% of the time are the same), will be different if the attribute value isn’t supported:

var testButton = document.createElement("button");
testButton.setAttribute("type","share");
if (testButton.type != "share") {
// polyfill
}

So that’s my modest proposal. Extend the list of possible values for the type attribute on the button element to include “share” (or something like that). In supporting browsers, it triggers a very bare-bones handover to the OS (the current URL and the current page title). In non-supporting browsers, it behaves like a button currently behaves.

Friday, August 28th, 2020

Why you should hire a frontend developer - Technology in government

This is a really good description of the role of a front-end developer.

That’s front end, not full stack.

Wednesday, August 26th, 2020

Submitting a form with datalist

I’m a big fan of HTML5’s datalist element and its elegant design. It’s a way to progressively enhance any input element into a combobox.

You use the list attribute on the input element to point to the ID of the associated datalist element.

<label for="homeworld">Your home planet</label>
<input type="text" name="homeworld" id="homeworld" list="planets">
<datalist id="planets">
 <option value="Mercury">
 <option value="Venus">
 <option value="Earth">
 <option value="Mars">
 <option value="Jupiter">
 <option value="Saturn">
 <option value="Uranus">
 <option value="Neptune">
</datalist>

It even works on input type="color", which is pretty cool!

The most common use case is as an autocomplete widget. That’s how I’m using it over on The Session, where the datalist is updated via Ajax every time the input is updated.

But let’s stick with a simple example, like the list of planets above. Suppose the user types “jup” …the datalist will show “Jupiter” as an option. The user can click on that option to automatically complete their input.

It would be handy if you could automatically submit the form when the user chooses a datalist option like this.

Well, tough luck.

The datalist element emits no events. There’s no way of telling if it has been clicked. This is something I’ve been trying to find a workaround for.

I got my hopes up when I read Amber’s excellent article about document.activeElement. But no, the focus stays on the input when the user clicks on an option in a datalist.

So if I can’t detect whether a datalist has been used, this best I can do is try to infer it. I know it’s not exactly the same thing, and it won’t be as reliable as true detection, but here’s my logic:

  • Keep track of the character count in the input element.
  • Every time the input is updated in any way, check the current character count against the last character count.
  • If the difference is greater than one, something interesting happened! Maybe the user pasted a value in …or maybe they used the datalist.
  • Loop through each of the options in the datalist.
  • If there’s an exact match with the current value of the input element, chances are the user chose that option from the datalist.
  • So submit the form!

Here’s how that translates into DOM scripting code:

document.querySelectorAll('input[list]').forEach( function (formfield) {
  var datalist = document.getElementById(formfield.getAttribute('list'));
  var lastlength = formfield.value.length;
  var checkInputValue = function (inputValue) {
    if (inputValue.length - lastlength > 1) {
      datalist.querySelectorAll('option').forEach( function (item) {
        if (item.value === inputValue) {
          formfield.form.submit();
        }
      });
    }
    lastlength = inputValue.length;
  };
  formfield.addEventListener('input', function () {
    checkInputValue(this.value);
  }, false);
});

I’ve made a gist with some added feature detection and mustard-cutting at the start. You should be able to drop it into just about any page that’s using datalist. It works even if the options in the datalist are dynamically updated, like the example on The Session.

It’s not foolproof. The inference relies on the difference between what was previously typed and what’s autocompleted to be more than one character. So in the planets example, if someone has type “Jupite” and then they choose “Jupiter” from the datalist, the form won’t automatically submit.

But still, I reckon it covers most common use cases. And like the datalist element itself, you can consider this functionality a progressive enhancement.

Tuesday, August 25th, 2020

The difference between aria-label and aria-labelledby - Tink - Léonie Watson

A handy reminder from Léonie (though remember that the best solution is to avoid the problem in the first place—if you avoid using ARIA, do that).

Sunday, August 16th, 2020

Web Technologies and Syntax | Jim Nielsen’s Weblog

Syntactic sugar can’t help you if you don’t understand how things work under the hood. Optional chaining in JavaScript and !important in CSS are ways of solving your immediate problem …but unless you know what you’re doing, they’re probably going to create new problems.

Saturday, August 1st, 2020

this vs that - What is the difference between ___ and ___ in the front-end development?

A handy reference for explaining the differences between confusingly similar bits of HTML, CSS, and JavaScript.

Friday, July 24th, 2020

Pausing a GIF with details/summary | CSS-Tricks

This is such a clever and useful technique! It’s HTML+CSS only, and it’s a far less annoying way to display animated GIFs.

(Does anybody even qualify the word GIF with the adjective “animated” anymore? Does anyone know that there used to be such a thing as non-animated GIFs and that they were everywhere?)

MSEdgeExplainers/explainer.md at main · MicrosoftEdge/MSEdgeExplainers

This is great! Ideas for allowing more styling of form controls. I agree with the goals 100% and I like the look of the proposed solutions too.

The team behind this are looking for feedback so be sure to share your thoughts (I’ll probably formulate mine into a blog post).

Saturday, July 18th, 2020

An Introduction To Stimulus.js — Smashing Magazine

An intro to Stimulus, the lightweight JavaScript library from Basecamp that takes a progressive enhancement approach, as seen with HEY.

One aspect I really like about the approach Stimulus encourages, is I can focus on sending HTML down the wire to my users, which is then jazzed up a little with JavaScript.

I’ve always been a fan of using the first few milliseconds of a user’s attention getting what I have to share with them — in front of them. Then worrying setting up the interaction layer while the user can start processing what they’re seeing.

Furthermore, if the JavaScript were to fail for whatever reason, the user can still see the content and interact with it without JavaScript.

Your blog doesn’t need a JavaScript framework /// Iain Bean

If the browser needs to parse 296kb of JavaScript to show a list of blog posts, that’s not Progressive Enhancement, it’s using the wrong tool for the job.

A good explanation of the hydration problem in tools like Gatsby.

JavaScript is a powerful language that can do some incredible things, but it’s incredibly easy to jump to using it too early in development, when you could be using HTML and CSS instead.

Thursday, July 16th, 2020

Hey now

Progressive enhancement is at the heart of everything I do on the web. It’s the bedrock of my speaking and writing too. Whether I’m writing about JavaScript, Ajax, HTML, or service workers, it’s always through the lens of progressive enhancement. Sometimes I explicitly bang the drum, like with Resilient Web Design. Other times I don’t mention it by name at all, and instead talk only about its benefits.

I sometimes get asked to name some examples of sites that still offer their core functionality even when JavaScript fails. I usually mention Amazon.com, although that has other issues. But quite often I find that a lot of the examples I might mention are dismissed as not being “web apps” (whatever that means).

The pushback I get usually takes the form of “Well, that approach is fine for websites, but it wouldn’t work something like Gmail.”

It’s always Gmail. Which is odd. Because if you really wanted to flummox me with a product or service that defies progressive enhancement, I’d have a hard time with something like, say, a game (although it would be pretty cool to build a text adventure that’s progressively enhanced into a first-person shooter). But an email client? That would work.

Identify core functionality.

Read emails. Write emails.

Make that functionality available using the simplest possible technology.

HTML for showing a list of emails, HTML for displaying the contents of the HTML, HTML for the form you write the response in.

Enhance!

Now add all the enhancements that improve the experience—keyboard shortcuts; Ajax instead of full-page refreshes; local storage, all that stuff.

Can you build something that works just like Gmail without using any JavaScript? No. But that’s not what progressive enhancement is about. It’s about providing the core functionality (reading and writing emails) with the simplest possible technology (HTML) and then enhancing using more powerful technologies (like JavaScript).

Progressive enhancement isn’t about making a choice between using simpler more robust technologies or using more advanced features; it’s about using simpler more robust technologies and then using more advanced features. Have your cake and eat it.

Fortunately I no longer need to run this thought experiment to imagine what it would be like if something like Gmail were built with a progressive enhancement approach. That’s what HEY is.

Sam Stephenson describes the approach they took:

HEY’s UI is 100% HTML over the wire. We render plain-old HTML pages on the server and send them to your browser encoded as text/html. No JSON APIs, no GraphQL, no React—just form submissions and links.

If you think that sounds like the web of 25 years ago, you’re right! Except the HEY front-end stack progressively enhances the “classic web” to work like the “2020 web,” with all the fidelity you’d expect from a well-built SPA.

See? It’s not either resilient or modern—it’s resilient and modern. Have your cake and eat it.

And yet this supremely sensible approach is not considered “modern” web development:

The architecture astronauts who, for the past decade, have been selling us on the necessity of React, Redux, and megabytes of JS, cannot comprehend the possibility of building an email app in 2020 with server-rendered HTML.

HEY isn’t perfect by any means—they’ve got a lot of work to do on their accessibility. But it’s good to have a nice short answer to the question “But what about something like Gmail?”

It reminds me of responsive web design:

When Ethan Marcotte demonstrated the power of responsive design, it was met with resistance. “Sure, a responsive design might work for a simple personal site but there’s no way it could scale to a large complex project.”

Then the Boston Globe launched its responsive site. Microsoft made their homepage responsive. The floodgates opened again.

It’s a similar story today. “Sure, progressive enhancement might work for a simple personal site, but there’s no way it could scale to a large complex project.”

The floodgates are ready to open. We just need you to create the poster child for resilient web design.

It looks like HEY might be that poster child.

I have to wonder if its coincidence or connected that this is a service that’s also tackling ethical issues like tracking? Their focus is very much on people above technology. They’ve taken a human-centric approach to their product and a human-centric approach to web development …because ultimately, that’s what progressive enhancement is.

Thursday, June 25th, 2020

Accessible to some - Manuel Matuzović

A score of 100 in Lighthouse or 0 errors in axe doesn’t mean that you’re done, it means that you’re ready to start manual testing and testing with real users, if possible.

Monday, June 22nd, 2020

Always bet on HTML | Go Make Things

I teach JS for a living. I’m obviously not saying “never use of JS” or “JavaScript has no place on the web.” Hell, their are even times where building a JS-first app makes sense.

But if I were going to bet on a web technology, it’s HTML. Always bet on HTML.

Saturday, June 13th, 2020

Striking a Balance Between Native and Custom Select Elements | CSS-Tricks

I think this a solution worthy of Solomon. In this case, the Gordian knot is the select element and its inevitable recreation in order to style it.

What if we instead deliver a native select by default and replace it with a more aesthetically pleasing one if possible? That’s where the “hybrid” select idea comes into action. It’s “hybrid” because it consists of two selects, showing the appropriate one at the right moment:

  • A native select, visible and accessible by default
  • A custom select, hidden until it’s safe to be interacted with a mouse

The implementation uses a genius combination of a hover media query and an adjacent sibling selector in CSS. It has been tested on a number of device/platform/browser combinations but more tests are welcome!

What I love about this solution is that it satisfies the stakeholders insisting on a custom component but doesn’t abandon all the built-in accessibility that you get from native form controls.

Friday, June 12th, 2020

HTML Tutorial for Beginners 101 (Including HTML5 Tags) - WebsiteSetup

A really great one-page guide to HTML from Bruce. I like his performance-focused intro:

If your site is based on good HTML, it will load fast. Browsers incrementally render HTML—that is, they will display a partially downloaded web page to the user while the browser awaits the remaining files from the server.

Modern fashionable development techniques, such as React, require a lot of JavaScript to be sent to the user. When it’s all downloaded, the user’s device must parse and execute the JavaScript before it can even start to construct the page. On a slow network, or on a cheaper, low-powered device, this can result in an excruciatingly slow load and is a heavy drain on the battery.

Wednesday, June 10th, 2020

Optimizing keyboard navigation using tabindex and ARIA — Sara Soueidan

Smart thinking from Sara to improve usability for keyboard users by using aria-hidden="true" tabindex="-1" to skip duplicate links:

A good rule of thumb for similar cases is that if you have multiple consecutive links to the same page, there is probably a chance to improve keyboard navigation by skipping some of those links to reduce the number of tab stops to one. The less tab stops, the better, as long as it does not worsen or compromise on other aspects of usability.

I’ve cautiously implemented this pattern now over on The Session where snippets of comments had both a title link and a “more” link going to the same destination.

Friday, May 29th, 2020

A Guide to the Responsive Images Syntax in HTML | CSS-Tricks

Chris has put together one of his indispensable deep dives, this time into responsive images. I can see myself referring back to this when I need to be reminded of the syntax of srcset and sizes.

Sunday, May 10th, 2020

Getting Started with the DOM

Here’s a short clear introduction to DOM scripting.

Monday, May 4th, 2020

A decade apart

Today marks ten years since the publication of HTML5 For Web Designers, the very first book from A Book Apart.

I’m so proud of that book, and so honoured that I was the first author published by the web’s finest purveyors of brief books. I mean, just look at the calibre of their output since my stumbling start!

Here’s what I wrote ten years ago.

Here’s what Jason wrote ten years ago.

Here’s what Mandy wrote ten years ago.

Here’s what Jeffrey wrote ten years ago.

They started something magnificent. Ten years on, with Katel at the helm, it’s going from strength to strength.

Happy birthday, little book! And happy birthday, A Book Apart! Here’s to another decade!

A Book Apart authors, 1-6