jQuery 4.0 Beta: Dropping IE Support and Major Changes You Need to Know

jQuery 4.0 Beta Highlights

The jQuery team recently released a 4.0 beta, announcing that support for Internet Explorer 10 and earlier versions has been removed. Support for IE will be completely dropped in the future 5.0 release, although that is still several years away.

According to BuiltWith statistics, more than 60% of the top 1 million websites still use the jQuery JavaScript library.

Timmy Willison, a jQuery team lead, noted that the amount of removed functionality in this version is roughly equal to the amount of new features. Support for many older browsers has been removed, including IE 11 and earlier, Edge Legacy (pre‑Chromium), iOS 11 and earlier, and Firefox 65 and earlier.

Willison also confirmed that IE support will be fully eliminated in jQuery 5.0.

Progress on the jQuery project has been relatively slow: the previous major release, jQuery 3.0 Final, was published in June 2016, and jQuery 4.0, originally planned for 2022, has been delayed several times.

When asked how long jQuery 3.x will be supported, maintainer Michał Gołębiowski‑Owczarek replied, “2026 is feasible for me, 2028 feels a bit far.”

jQuery 4.0 drops support for about a dozen deprecated APIs—most of which were internal or now have native equivalents in all supported browsers. The order of focus and blur event triggering has also been changed.

FormData support has been enhanced to handle binary data, enabling direct transmission of files to the server. Willison described this as “technically a breakthrough change, but it should behave as expected.”

Although these changes are significant, upgrading from jQuery 3.x usually does not cause compatibility problems; upgrading from 2.x may introduce more bugs.

Development methodology has shifted as well: starting with version 4.0, jQuery is built as an ES (ECMAScript) module and bundled with Rollup instead of RequireJS.

jQuery’s original purpose was to simplify JavaScript programming and provide polyfills for features missing in older browsers. As the usage of Microsoft’s Trident engine (used by IE and Edge Legacy) declines, jQuery becomes less essential in some scenarios, prompting sites like “You might not need jQuery” to showcase native alternatives. Nevertheless, jQuery remains deeply embedded in the web ecosystem, with many popular libraries and frameworks still relying on it.

Developers are divided on whether to avoid jQuery in new code. Some have abandoned it in favor of vanilla JavaScript, claiming the native language now offers everything jQuery provided. Others argue that jQuery remains a widely supported, extremely stable toolkit for DOM selection, attribute manipulation, Ajax, event handling, animation, and general utilities, especially when native equivalents are not yet smooth.