Articles in the ‘HTML5’ Category

Notes from Edge Conf 2014 London

I was lucky enough to be invited to attend and speak at Edge Conf London 2014, an assembly of web development superheroes charged with discussing the future of web technology in front of a live audience. I’ve written up my main take-aways from the event.

Web Components

Web Components Panel at EdgeConf  3 Web Components Panel at EdgeConf 3

  • Web Components are the custom elements that you’ve always wanted. If you’re after a <google-map> tag, web components can give it to you.
  • The basics are registering a new element with the DOM, then you can do anything
  • Web components are imported with a HTML link element: <link import=”component.html”>
  • To make these components useful, you need to use the Shadow DOM – this is the DOM inside an element, which is already being used on the web: take a look inside Chrome’s dev tools at an <input type=”range”> element – tickers are <button> elements inside the <input>
  • There are no browsers that support this out of the box yet, so there are two polyfills that you can use: Polymer (Google) and X-Tags (Mozilla)
  • The Server/Client rendering trade-off is the concern at the moment. Any JS downloading in a web component will block rendering unless specified as async. You can also compress and minify web components and their resources, which is a necessary step to get anywhere near good performance. We’re adding new tools, but the old techniques still apply.
  • Responsive components, that have media queries related to their own size, aren’t possible because they could be influenced by the parent too, which will get the rendering engine into infinite loops.
  • On semantics and accessibility: they are still important, but with ARIA roles not caring what element they are on, you can make anything appear like anything, so the argument that web components are bad for semantics is kinda moot.
  • On SEO, the usual rules still apply, you’ve got to make your content accessible and not hide it, but the search bots will read web components
  • On styling, using scoped styles (a level 4 spec) works very well, as these will override at scope. However, using an object-oriented CSS approach makes this easier. It is, however, generally harder to make all of your CSS into OOCSS, which is more of a team/rigour problem.
  • In the end, you’re responsible for packaging and de-duplicating your resources. Web components will remove any duplicate files from the same origin, but it’s still very easy to import two versions of jQuery. You are responsible for that.

Bruce Lawson has another very good write-up on this session, and web components in general on his blog.

Developer Tooling

Developer Tooling Panel at Edge Conf 3 Developer Tooling Panel

  • Firefox’s in-built developer tooling has come a long way from Firebug, with new features like deep scoping of function variables, great memory profiling and visual descriptions of CSS transforms
  • Chrome’s dev tools will have a better call stack flame graph
  • Brackets does great in-line CSS editing and rendering
  • Remote Debug aims to solve the complex workflow issue, where a developer knows how to use Chrome’s dev tools, but not Firefox’s, and it will let you use Chrome’s tools with Firefox.
  • JS Promises aren’t in the dev tools sets yet. We need to experiment with the technology and then make tools. We can’t make tools for something that doesn’t exist yet
  • Use debugger; rather than console.log – you may as well use alert()
  • It would be great if we could inspect headless browsers with dev tools so that we can see what went on with a test
  • It was also noted that contributing to dev tools is harder than it could be. Remy Sharp suggested creating some kind of Greasemonkey scripting capability for dev tools

Build Tools

Build Process panel at Edge Conf 3 Build Process panel

  •  Building software is not new. The Unix make command is 37 years old.
  • We are trying to avoid a plugin apocalypse with grunt, gulp, bruch etc re-inventing the wheel
  • A big mention in this session of the Extensible Web Manifesto as a basis for how we should be developing these tools
  • There are things that belong in our build process, and things that belong in our browser. With Sass, variables should be in the browser, but minification and compilation should not.
  • As a community, we need to be responsible with what we put into the standards
  • Having NodeJS as a dependency is reasonable right now. However, we should standardise our tools on JavaScript, rather than on NodeJS. Node is a runtime, and it will be superseded eventually.
  • Use git, not github. Use the npm protocol, not npm. The basics are great, but we can’t rely on services like this
  • More tools fuel innovation. A single task spec as a way to describe tasks between the task runners would be great, but this is on hold as they currently can’t agree.
  • On Grunt/Gulp – use the tool you’re comfortable with, and make the most of it.
  • We are still in the early days of build tools. Being locked in to a certain tools for 5 years probably won’t hurt, because at least you’re using a build tool!

Page Load Performance

  • “Put it in the first 15KB for ultimate performance”. Load content first, then enhancements, then the leftovers, and you’ll get great performance
  • Use sitespeed.io and webpagetest for your synthetic testing
  • Looking at The Guardian – their branched loading model saves them 42% with their responsive site
  • There will still be times when an adaptive site, with proper redirects, will give you better performance. I can vouch for this: Yell.com on the desktop is around 700KB, the homepage on mobile is around 60KB.
  • HTTP2 will make spriting an anti-pattern, as it makes it easier to only download what you need. Remember, it’s only the network that needs the data in one file
  • If you own your site, instrument it. Target StartRenderTime, and use Window.performance for better timing. Look to improve the Page OnLoad Event.
  • Resource Priorities and timing APIs will arrive soon. You’re encouraged to use these in your Real User Monitoring (RUM) stats. Not many companies do this at the moment.
  • Finding out is a user is getting page jank is a hard problem as you’d have to hook into RequestAnimationFrame

Pointers and Interactions

I was on this panel, so I’ve not got any notes! Thankfully, Google were there to video it for everyone

Accessibility

Accessibility panel at EdgeConf 3 Accessibility Panel

  • For accessibility, complying to geo-specific regulations is important, but, complying with the law doesn’t make your website accessible
  • Are WCAG guidelines outdated? No, their values are still good, but there are more complex use cases since it was written. For example, gaming accessibility is about making visual cues auditory
  • Mechanical audits of a website don’t give you the full accessibility brief. It can give you ARIA roles, colour contrast, click regions and alt-text etc
  • Try the Chrome Accessibility Tools extension, and the SEE extension, to see your page though different eyes
  • If you want to know what it feels like to have a muscular problem, try using your mouse with you non-writing hand
  • Accessibility needs to be considered at the design stage – if done at the QA stage, you’ve missed the point

Future Web

Sadly, I wasn’t at the event for this, but here’s the video for you all to enjoy

Related Reading

I loved the conference, I’ve not learnt so much in a day in years! Here are some other write-ups from around the web:

Going jQuery-free

It’s 2014 and I’m feeling inspired to change my ways. In 2014, I want to go jQuery-free!

Before I get started, I want to clear the air and put in a big fat disclaimer about my opinions on jQuery. Here we go:

jQuery is an excellent library. It is the right answer for the vast majority of websites and developers and is still the best way to do cross-browser JavaScript. What I am against is the notion of that jQuery is the answer to all JavaScript problems.

Lovely, now that’s done, this is why I want to do it. Firstly, as lots of people know, jQuery is quite a weighty library considering what it does. Coming in at 32KB for version 2.x and around 40KB for the IE-compatible (gzipped and minified), it’s a significant chunk of page weight before you’ve even started using it. There are alternatives that support the majority of its functions in the same API, such as Zepto, but even that comes in at around 15KB for the most recent version, and can grow larger. The worst thing for me, is that I don’t use half of the library, all I really do is select elements, use event handlers and delegation, show/hide things and change CSS classes. So, I want a library of utility functions that only does these things.

Word to the wise, this is not a new notion, and follows on very nicely from the work that Remy Sharp has done in this area in his min.js library.

I’m going to write a series of posts as I attempt to separate myself from jQuery, and make my websites leaner and faster. The first of which will be on “what you think you need, and what you actually need” and give you ways to work out if this approach is for you, or if you should be sticking with jQuery. Next, I’ll cover the basics of what a minimalist jQuery library; and finally I’ll cover strategies for dealing with unsupported browsers.

Let me know if there’s anything in particular you want me to cover, and I’ll do my best to go over it for you.

The web standards project – job done

“Our work here is done” – the immortal final words of the web standards project. Please, read the post, for me it’s a tearjerker, and I’ll tell you why.

Before I left uni, when I still didn’t know what I wanted to do, I found the WaSP group online and thought, “that’s amazing – people from all walks of life and competing companies no less, all getting together to make possibly the world’s most important invention a better place. I want to do what they do”

Many years later, as the web standards project closes its doors, I help to run a web standards meetup group, speak at conferences on web standards and evangelise their use every day. Thank you WaSP members for inspiring me to be where I am today.

Thank you so much

CSS3 Object-fit Polyfill

TL;DR; I’ve made a polyfill for CSS3 Object-fit. Download it from Github here: https://github.com/steveworkman/jquery-object-fit

The need for object-fit

A month ago, I was looking into creating a responsive grid full of images for a client. The width of the columns would vary depending upon device, and the dimensions and aspect ratio of the provided images could not be guaranteed.

The issue for me is keeping the images looking great, without skewing the dimensions and distorting the results, but I also needed them to expand or shrink to fit the boxes that they had been provided with.

A skewed picture

Knowing CSS, the property background-size: cover|contain would do this perfectly (See this A List Apart article for lots more detail), but this is for background images, and semantically, the images in my grid are part of the content, so should not be background images.
Looking for an equivalent, I found Object-fit: part of the CSS3 Image Values and Replaced Content spec. Unfortunately, browser support for this is very poor; this is the current browser implementation of this property:

As you can see, as of September 2012, only Opera support this feature! Side note: there is one other browser (there has to be for this to be for the spec to reach candidate recommendation) which is the HP TouchPad, not very useful for the majority of users

This isn’t going to get anyone very far, given that over 90% of all browser usage doesn’t support this feature. So, whilst browsers catch up, we have to use a polyfill to re-create this functionality with JavaScript.

Object-fit polyfill

The polyfill is based on jquery-object-fit by Simon Schmid, to which I’ve made some improvements:

  • Added support for cover
  • Fixed the implementation for IE and Firefox
  • Added feature detection so it uses the native implementation where possible
  • Made it re-calculate on resizing the browser for responsive layouts
  • Added a more tests to the suite

The results

Object-Fit tests

Object-fit grid of images

A responsive grid of images with the correct aspect ratios

What you get is a simple polyfill for object-fit which follows the spec as closely as it can. There is one main difference:

  • In a native implementation the image size remains the same and the picture within the image changes its dimensions, revealing grey letterboxed content. In the poly fill, an extra div is created around the image to take its dimensions and then the image is resized within that to provide the effect.

The source code is on github so please contribute if you can. I’ll be keeping this up-to-date so follow me @steveworkman on Twitter for the latest updates.

My thanks to Chris Mills of Opera for his articles and helping to explain how on earth all this works, and to Tab Atkins and the CSS WG for spelling it out. Hopefully there will be some more work on this feature soon. You can track the status of its implementation in Gecko (Firefox) and Webkit (Chrome et al) on their bug trackers (see links).

Please, let me know what you think in the comments and on github.