Upgrading
We do not expect compatibility issues when upgrading from a jQuery 3.0+ version. If you haven’t yet upgraded to jQuery 3.0, have a look at the 3.5 Upgrade Guide and 3.0 Upgrade Guide.
The jQuery Migrate plugin will help you to identify compatibility issues in your code. Please try out this beta release and let us know about any issues you experience.
If you can’t yet upgrade to 3.5+, Daniel Ruf has kindly provided patches for previous jQuery versions.
Updated slim build
The slim build has gotten even smaller in jQuery 4.0.0 with the removal of Deferreds and Callbacks (now below 20k bytes gzipped!). Deferreds have long-supported the Promises A+ standard, so native Promises can be used instead in most cases and they are available in all of jQuery’s supported browsers except IE11. Deferreds do have some extra features that native Promises do not support, but most usage can be migrated to Promise methods. If you need to support IE11, it’s best to use the main build or add a polyfill for native Promises.
Download
You can get the files from the jQuery CDN, or link to them directly:
https://code.jquery.com/jquery-4.0.0-beta.js
https://code.jquery.com/jquery-4.0.0-beta.min.js
You can also get this release from npm:
Slim build
Sometimes you don’t need ajax, or you prefer to use one of the many standalone libraries that focus on ajax requests. And often it is simpler to use a combination of CSS and class manipulation for web animations. Finally, all of jQuery’s supported browsers (except for IE11) now have support for native Promises across the board, so Deferreds and Callbacks are no longer needed in most cases. Along with the regular version of jQuery that includes everything, we’ve released a “slim” version that excludes these modules. The size of jQuery is very rarely a load performance concern these days, but the slim build is about 8k gzipped bytes smaller than the regular version. These files are also available in the npm package and on the CDN:
https://code.jquery.com/jquery-4.0.0-beta.slim.js
https://code.jquery.com/jquery-4.0.0-beta.slim.min.js
These updates are already available as the current versions on npm and Bower. Information on all the ways to get jQuery is available at https://jquery.com/download/. Public CDNs receive their copies today, please give them a few days to post the files. If you’re anxious to get a quick start, use the files on our CDN until they have a chance to update.
Thanks
Thank you to all of you who participated in this release by submitting patches, reporting bugs, or testing, including Alex, Ahmed S. El-Afifi, fecore1, Dallas Fraser, Richard Gibson, Michał Gołębiowski-Owczarek, Pierre Grimaud, Gabriela Gutierrez, Jonathan, Necmettin Karakaya, Anders Kaseorg, Wonseop Kim, Simon Legner, Shashanka Nataraj, Pat O’Callaghan, Christian Oliff, Dimitri Papadopoulos Orfanos, Wonhyoung Park, Bruno PIERRE, Baoshuo Ren, Beatriz Rezener, Sean Robinson, Ed Sanders, Timo Tijhof, Tom, Christian Wenz, ygj6 and the whole jQuery team.
We’re on Mastodon!
jQuery now has its very own Mastodon account. We will be cross posting to both Twitter and Mastodon from now on. Also, you may be interested in following some of our team members that have Mastodon accounts.