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GOV.UK drops jQuery from their front end.

GOV.UK dropped their jQuery dependency from their front end. You'll
never
guess what happened. (Yes, you will.)

May 19, 2022
Jeremy Wagner
Jeremy Wagner
TwitterGitHubHomepage

jQuery is a roughly 30 KiB dependency that nearly 84% of mobile pages
used in 2021--and for good reason. jQuery was an instrumental tool in
a time when we really needed a way to script interactivity in a way
that smoothed over the differing implementations of stuff like event
handling, selecting elements, animating elements, and so on.

The web is better because of jQuery--not just because it has such
incredible utility, but because its ubiquity led to making what it
provided part of the web platform itself. Nowadays, we can do just
about anything jQuery can do in vanilla JavaScript:

  * We can select elements using a CSS selector syntax with
    querySelector and querySelectorAll.
  * We can add, remove, and toggle classes on elements with the
    classList API.
  * We can attach event handlers to DOM elements and the window using
    addEventListener.
  * And so, so, much more.

It really begs the question: Do we really need jQuery today? That's a
question that GOV.UK has answered with a resounding "no". In March of
2022, Matt Hobbs announced that GOV.UK removed their jQuery
dependency. This is a big deal when it comes to the user experience,
because GOV.UK provides services and information online for The
United Kingdom at scale. Not everyone is tapping away on their 2022
MacBook Pro on a rip-roarin' broadband connection. GOV.UK has to be
accessible to everyone, and that means keepin' it lean.

Here's a few of the greatest hits from Matt Hobbs on what GOV.UK
noticed in removing jQuery:

  * Less front end processing time overall.
  * 11% less blocking time at the 75th percentile.
  * 10% less blocking time for users at the 95th percentile. These
    are users who experience seriously adverse network and device
    conditions, and every performance gain matters especially for
    them.

For the full story, check out Matt's informative Twitter thread. It's
great stuff for web performance geeks, and drives home the point that
dependencies matter when it comes to performance. Don't shortchange
your users if the web platform can easily do the job a framework can.

This level of commitment to the user experience from a institution
that works at the scale GOV.UK does is commendable. I can only hope
others follow in their footsteps.
PerformanceJavaScript
Last updated: May 19, 2022 -- Improve article
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