What browsers do you need to support?
If you have to support IE8 I do not recommend that you ditch jQuery. IE8 doesn’t have many of the fundamentals to be considered “modern” and work without significant polyfilling in a way that modern Webkit browsers do. The Guardian uses a simple script to detect whether your browser is modern:
isModernBrowser:('querySelector'in document&&'addEventListener'in window&&'localStorage'in window&&'sessionStorage'in window&&'bind'in Function&&(('XMLHttpRequest'in window&&'withCredentials'in new XMLHttpRequest())||'XDomainRequest'in window))
This checks for the following functions:
Local Storage and Session Storage
CORS (Cross-origin resource scripting)
If you’re modern, The Guardian will give you everything. If not, you get a gracefully degraded experience. IE8 will fail all but the local storage part of that test, and polyfilling that much code will negate all the benefits of removing jQuery.
With some browsers, it is possible to polyfill small parts of this functionality and still remove jQuery. For example, Yell supports iOS 4 and above, which doesn’t have Function.bind, Android 2.3 doesn’t support Element.ClassList or SVG, and IE10 doesn’t support Element.data. We chose to polyfill these functions for the older browsers, but not SVG or Element.data, as these can be resolved by other techniques or just coding differently.
There will be plenty of times that you will be able to find alternatives to plugins that work without jQuery. The simple way to find them is to use Google, Github, StackOverflow and Twitter to search for alternatives. I wish that there was a repository that told you the good alternatives for common jQuery plugins – but there isn’t one (note to self: do this). This can be laborious, and involve a lot of trial and error to find alternatives that match the feature set you’re looking for.
I went through this same process with my team for yell.com’s mobile site. Luckily, there was only one plugin that we needed to keep, Photoswipe – a cool plugin that creates a touch-friendly lightbox from a list of images. We looked high and low for vanilla JS alternatives that 1. were mobile-friendly, and 2. worked on Windows Phone 8 & Firefox OS and Firefox mobile. That last part was the hard bit, and I’m sad to say that we didn’t find an answer. So, we had to build this ourselves – you can see it on any business profile page on your smartphone like this one (though you’ll have to change your browser user agent to a mobile phone to see it).
TL;DR: you’ll need to find replacements for all plugins, and if you don’t, your options are to write it yourself, or drop the functionality.
Once you’ve found solutions for third party code, you need to focus on your own custom code. To find out what could break, you’ll need to look over your JS and see what jQuery methods and properties are in use. You can do this manually, but I don’t fancy looking over 10,000 lines of code by hand. I asked “how can I do this” on Stack Overflow and got a great answer from Elias Dorneles:
You can run this on one file, or an entire directory. Here’s what Bootstrap.js looks like (after I’ve tabulated it in excel):
This is the list of functions that you will have to find alternatives to in order for your JS to function correctly, along with an approximate count of the number of times a function is used. I say approximate, because in my experience, the grasp script doesn’t get everything, especially where chained functions are concerned. The good news with this set is that there aren’t many complex functions in use – the vast majority can be replaced with a line or two.
The results of this query can bring back all sorts of jQuery functions, things like .live, .die, .delegate, .browser, .size, .toggle, and other deprecated functions from over the years. These are the warning signs that the rest of your code may not be ready for a move away from jQuery, and if you get these, you should seriously consider why you’re doing this. I listed my reasons in the introduction post and there are more besides, like minimal memory footprint whilst adding Windows Phone 8 and Firefox OS support. You may end up spending a lot more effort on your code than you originally intended, just to bring it up to par with the current state of web standards. Clearly, this isn’t a bad thing, but your boss may be wondering why it’s taking so much time. For a great article on technical debt, try Paying Down your Technical Debt from Chris Atwood’s Coding Horror site.
Up next, replacing individual functions with standards-based code
That’s it for this part, in the next one, I’ll cover replacing the functions identified above with standards-compliant code to create your own min.js.
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 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.
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
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
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:
Lovely, now that’s done, this is why I want to do it. Firstly, as lotsof peopleknow, 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.
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.
“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.