jQuery 4.0.0 Released, First Major Version Upgrade in Nearly 10 Years, Finally Ends Support for IE10 and Earlier
The stable version of jQuery 4.0.0 , the first major version update in about 10 years for the JavaScript library
jQuery 4.0.0 | Official jQuery Blog
https://blog.jquery.com/2026/01/17/jquery-4-0-0/
The beta version of jQuery 4.0 was released in February 2024, and this latest release is the stable version after a long development cycle and multiple pre-releases. This major version upgrade marks the 20th anniversary of jQuery's release on January 14, 2006.
jQuery 4.0 ended support for IE10 and earlier. IE support will be phased out, with jQuery 5.0 being the next step. Additionally, support for older browsers, such as the pre-Chromium Microsoft Edge, iOS 16 and earlier, Firefox versions earlier than 146 (excluding ESR), and Android Browser, has also been discontinued. If you use these browsers, it is recommended that you use jQuery 3.x.
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Additionally, many APIs that have been deprecated for many years have been removed, such as functions like jQuery.trim, jQuery.isArray, jQuery.parseJSON, jQuery.now, and jQuery.isFunction being deprecated, and requiring migration to native functions like Array.isArray(), JSON.parse(), and Date.now(). Additionally, internal methods like push, sort, and splice have also been removed from the jQuery prototype.
In terms of security, we've added support for Trusted Types, making it less likely to violate the require-trusted-types-for directive when passing HTML strings wrapped as TrustedHTML to jQuery DOM manipulation methods. Additionally, we've moved towards using script tags whenever possible to avoid CSP errors when retrieving asynchronous scripts.
Additionally, source code management has been migrated from AMD to ES modules, and the adoption of Rollup as the packaging tool improves compatibility with modern build tools, development workflows, and browser script type=module.
The event system has been revised to ensure that focus event firing order conforms to the W3C specification. Starting with jQuery 4.0, focus events will no longer override native behavior and will follow the current specification order in all browsers except IE.
The file size has also been optimized, with the removal of deprecated APIs and code for older versions of Internet Explorer resulting in a reduction of over 3kB in gzipped form. Furthermore, the slim build version, which excludes Ajax and animation-related modules, also now excludes Deferreds and Callbacks, resulting in a file size of approximately 8kB lighter than the standard version, at approximately 19.5kB.
To assist with the migration, an upgrade guide and the jQuery Migrate plugin are available, and it is said that most projects can be updated with minimal code changes.
A group photo of the members who have supported jQuery's development for 20 years, including its creator John Resig , has been published on the jQuery blog.
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in Software, Posted by log1i_yk