jQuery Core: Version 1.9 and Beyond

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Please check out the followup post before jumping to the wrong conclusion.

As the last blog post discussed, jQuery version 1.8 is undergoing a spring cleaning to remove insecure, inefficient, ineffective, and inadvisable features. We’ve also begun the work to allow you to build custom versions that exclude parts of the library for even greater savings. Those efforts will make it possible for you to enjoy the jQuery API you need without carrying around the parts you don’t want.

Now that we’ve cleaned house, it’s time to take a look forward. There’s just one thing interfering with our vision of the future, and that’s the ghost of browsers past. Internet Explorer 6, 7, and 8–collectively, oldIE–have been a thorn in the side of web developers for a decade. Collectively, these browsers of a bygone era still represent up to one-third of users visiting some sites. That is a lot of users–people who still want the information, services and products that web sites provide. For many web sites that use jQuery, it’s not practical or profitable to ignore that audience.

jQuery was conceived specifically to address the differences in browsers, so we’re not going to abandon the essence of our philosophy and simply disregard the millions of active Internet users who (for whatever reasons) still use oldIE. Yet we also want to move ahead and take advantage of modern browsers, especially the growing mobile market.

The Road Ahead

jQuery 1.8 should arrive within a month. Here is our thinking about the next two versions of jQuery to follow it, and when they’ll arrive:

  • jQuery 1.9 (early 2013): We’ll remove many of the interfaces already deprecated in version 1.8; some of them will be available as plugins or alternative APIs supported by the jQuery project. IE 6/7/8 will be supported as today.
  • jQuery 1.9.x (ongoing in 2013 and beyond): This version will continue to get fixes for any regressions, new browser bugs, etc.
  • jQuery 2.0 (early 2013, not long after 1.9): This version will support the same APIs as jQuery 1.9 does, but removes support for IE 6/7/8 oddities such as borked event model, IE7 “attroperties”, HTML5 shims, etc.

Our goal is for 1.9 and 2.0 to be interchangeable as far as the API set they support. When 2.0 comes out, your decision on which version to choose should be as simple as this: If you need IE 6/7/8 support, choose 1.9; otherwise you can use either 1.9 or 2.0.

Questions and Answers

If jQuery 1.9 and 2.0 are basically the same API, what makes 2.0 compelling? Smaller size, better performance, and the lack of problems introduced by the need for oldIE support. We expect that we can improve error handling in the $.Deferred implementation in 2.0, for example, whereas we can’t do that as long as oldIE is supported.

My site still has many IE7/8 visitors but I want to use jQuery 2.0. Can I do that? If your web site needs oldIE support, and we expect most sites will need it for at least another year or two, you can use IE conditional comments to include version 1.9 only when visitors are using oldIE:

<!--[if lt IE 9]>
    <script src="jquery-1.9.0.js"></script>
<!--[if gte IE 9]><!-->
    <script src="jquery-2.0.0.js"></script>

Why not make an “oldIE plugin” for jQuery 2.0? Special dispensations for oldIE are sprinkled throughout jQuery. Refactoring the code to provide enough hooks so that oldIE support could be added as a plugin would complicate the code for the modern browser case. Plus, developers supporting oldIE and using a public CDN would then need to include two files (jQuery 2.0 and the oldIE plugin) instead of one.

Once jQuery 2.0 is released, what happens to 1.9? In a departure from the past, we’ll continue to fix bugs in 1.9 (as minor releases). Having just gone through a spring cleaning for 1.8 and 1.9, we don’t anticipate adding a lot of new APIs in the future. Instead, we prefer to add new functionality through plugins compatible with both versions where it makes sense. So don’t feel like you’re being left behind when using version 1.9.

Is jQuery 2.0 basically for mobile devices? No. Although jQuery 2.0 will be a great fit for HTML mobile apps, including ones written with jQuery Mobile, it is not a Webkit-only library that targets just iOS and Android. In addition to mobile browsers, 2.0 will support (and be tested!) with modern desktop versions of Internet Explorer, Opera, Firefox, Safari, and Chrome.

How much smaller/faster will jQuery 2.0 be? We won’t know until we’re done, or at least close to being done. You can bet that we’ll tell you more as the release date for 2.0 draws near. Better yet, you can try the beta when it is released and see for yourself!

jQuery 1.8 Beta 1: See What’s Coming (and Going!)

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Hello fellow jQuery users! It’s been a while since you’ve heard from us, but we haven’t been asleep. The jQuery Core Team has been heads-down working on jQuery 1.8, and our first beta release is now available! You can get the code from the jQuery CDN:

Give it a try on your current jQuery code and let us know how it works for you. If you experience issues, please file a bug, include a test case, and be sure to mention that you’re testing against jQuery 1.8 Beta 1.

There will be even more exciting jQuery news at the jQuery Conference in San Francisco later this month, with blog posts to follow.

jQuery is now powering about one-half of all the major web sites on the Internet; that’s a great success, but we’re not standing still. Web browsers and the devices they run on have undergone an incredible metamorphosis in the past six years. The process of web development is evolving to accommodate the changes that are happening. In response, jQuery continues to evolve as well.

Part of that evolution is not just knowing what to add, but what to take away. jQuery’s plugin architecture makes it easy for developers to extend the functionality that jQuery Core offers when it makes sense for their own needs. For that reason, the bar has been set pretty high for additions to Core. We don’t want to create size, complexity, or performance penalties for people who don’t need specific features.

Similarly, we have enough experience with the way that people use jQuery to know some features that originally seemed like a good idea turned out to be a not-so-good idea. Rather than carry these around forever, we want to remove them eventually. In fact, we want to make it easier to create a version of jQuery that excludes things you don’t need or want, especially for mobile environments where space can be precious.

With that in mind, here are some changes we are planning for jQuery 1.8 that will make it a better foundation for all HTML-based web pages and applications, regardless of their platform:


As of jQuery 1.8, you can build a custom version of jQuery that excludes one or more modules if you do not need their functionality. This capability is made easy by our new build system based on Ben Alman’s awesome grunt tool. To build your own custom version, set up a copy of the jQuery core repo from Github and use the grunt command line options to exclude modules. For more information, see the README file.

The modules you can currently exclude are ajax, css, dimensions, effects, and offset. For example, if your application exclusively uses stylesheets and CSS animations via classes to control the visibility and size of items on the page, you could build a version without the css, dimensions, effects, and offset modules. If you didn’t need any of the optional modules, your custom build of jQuery would be about 21KB minified and gzipped.

Don’t worry though, building your own jQuery is completely optional. jQuery has always been, and will continue to be, distributed as a single file in both compressed and uncompressed form and available on CDNs. We still expect that to be the way most jQuery developers go, because it’s simple and painless. For example, when you include a jQuery plugin that you didn’t write, using the full jQuery ensures you won’t be bitten by some dependency lurking inside the plugin.

Vendor-Prefixed CSS Properties

The W3C had its heart in the right place when it came up with the idea to use vendor prefixes for CSS features that were not yet standardized, but it hasn’t resulted in a fairy-tale ending. Web developers are faced with the nightmare of including all the vendor-prefixed property names in stylesheets. jQuery 1.8 eases the pain a bit. We automatically take the non-prefixed property name and generate the prefix that is appropriate for the current browser, so you don’t have to. For example, on Chrome the jQuery call $("#myscroll").css("marquee-direction", "backwards") will set the CSS to -webkit-marquee-direction: backwards.

Animation (Effects)

Our code for animation had become a tangled mess over the past few years, and with 1.8 we hope we’ve brought the beast under control. It’s more than just a cleanup, though; there are several extension points that make it easier to add or modify animations. At the moment there is only preliminary documentation for the new features, but in this first beta our primary focus will be on ensuring that any existing animation code works properly.

Browsers are doing a much better job providing efficient animations today, particularly with CSS transitions. Yet there are still plenty of users who don’t have a browser capable of doing CSS-based animations. With jQuery 1.8 you get the best of both worlds. If you need to support older browsers without built-in animations, the new $.Animation provides a solid foundation and fixes many bugs from previous versions. If you need to target only modern browsers and their natively supported animations, you can do that and exclude the animation module entirely.

Sizzle CSS Selector Engine

jQuery’s selector engine has undergone a major rewrite in 1.8. The most notable benefit of this rewrite is a widespread performance improvement of selector matching as well as improved shortcuts for the most common selectors.

Additionally, Sizzle handles many more edge cases and bugs, including improved support for multiple combinators (~ > +) and better detection of browser bugs in querySelectorAll. See the bugs list below in the selector module for a complete list.

XSS Protection

By design, the $() method can create HTML elements, and will run scripts if it is passed a <script> tag with inline script or a src attribute. Developers have sometimes forgotten this, passing strings to jQuery that come from untrusted sources such as the URL or user input. In these cases, it is possible for someone to inject a script into the page that can steal cookies or compromise the page in some way.

These cross-site-scripting (XSS) attacks are common on many sites whether they use jQuery or not, but we want to ensure jQuery does not contribute to the problem. In jQuery 1.9 (the NEXT version following 1.8), we’re tightening down the “looks like HTML” rule for the $() method. A string will only be considered HTML if the first character is a less-than sign, otherwise it will be assumed to be a CSS selector.

As further protection against the inadvertent injection of scripts, jQuery 1.8 introduces a new method: $.parseHTML. It lets you specify strings as HTML and know that they will be parsed as HTML, something that $() cannot do since it also interprets strings as selectors. It also provides a way to parse HTML into a DOM fragment and control the execution of any scripts the HTML it may contain. This is particularly important in JavaScript environments controlled by Content Security Policy (CSP), since injected scripts may cause security warnings or exceptions.

For anything more than the simple case of creating single elements (e.g., $("<p/>")), and particularly for cases where strings are built from external data, we strongly recommend using $.parseHTML. As of jQuery 1.9, some HTML strings will no longer be recognized by $() as a result of these stricter rules.

Spring Cleaning

In jQuery 1.8 we’ll also be deprecating and removing “trip hazards”: APIs and features that are inefficient, ineffective or inadvisable. We realize that there will be existing jQuery code that still requires these features. To provide a low-hassle future upgrade path, we’ll be providing many of the deprecated items in a compatibility plugin after they are removed. You can follow the compatibility plugin as it is developed on its GitHub repo.

Tickets below that begin with “Deprecate” or “Remove” tell the whole story of what is changed, but here are a few changes of particular note:

$.browser: Ever since jQuery 1.4, we’ve been evangelizing that browser detection via the user agent string is a bad idea. Yet we’ve been an enabler of bad practice by continuing to offer $.browser. As of jQuery 1.9 we’ll remove it entirely and you’ll need to use the 1.9 compat plugin. If your code isn’t weaned off browser detection yet, check out Modernizr for a very thorough set of feature detections you can use instead. And of course, you’re welcome to read the tea leaves in the navigator.userAgent string directly, there’s nothing stopping you but your conscience.

$.sub: This method was introduced in jQuery 1.5, but hasn’t proved to be useful or robust enough to justify it staying in core. It will move to a compatibility plugin in jQuery 1.9.

Global ajax events: Events such as ajaxStart fired by $.ajax can currently be attached to any element–even to elements that are not in a document at all! This creates an inefficient special case, so we are deprecating that behavior in 1.8. Ajax events should be attached only on document as of 1.9.

And Much Much More…

There are many other changes in 1.8, perhaps the easiest way to see what we’ve been up to is to look at the list of issues that are being fixed, which includes both features and bug fixes. Here is a snapshot of 1.8 as it stands today, but it’s not set in stone. We welcome your feedback about specific issues or the direction of jQuery in general!

jQuery 1.8 Beta 1 Change Log

The current change log of the 1.8 Beta 1 release.


  • #8205: JSONP random result is causing memory leak in IE8
  • #8653: jQuery.param outputs "null" and "undefined" in the query string
  • #10285: evalScript rcleanScript replacement fails in IE8
  • #10524: jQuery.fn.load does not merge data parameter with jQuery.ajaxSetup
  • #10944: $.ajax does not always return an object implementing the Promise interface
  • #11013: Deprecate/remove async option from $.ajax
  • #11402: evalScript function fails with error error 80020101 in IE
  • #11743: jQuery silently ignores errors during script tag ajax request in $.appendTo()
  • #11778: Cached XHR requests should still resolve asynchronously


  • #11153: jQuery 1.7 Strips Carriage Returns in IE 8
  • #11212: Sizzle.getText converts unbreakable space into whitespace on IE


  • #11767: Support custom build without effects
  • #11789: Update README to describe grunt build system
  • #11856: modularize dimensions
  • #11857: modularize css
  • #11865: modularize offset


  • #10657: Deprecate/remove jQuery#size() in favor of jQuery#length
  • #11290: selector interpreted as HTML
  • #11470: Adding a builtin readyP promise


  • #10373: `document.defaultView` => `window`
  • #10413: width, innerWidth, innerHeight, outerWidth, outerHeight are inaccurate for a "box-sizing: border-box" child of hidden parent
  • #10679: CSS3 vendor prefix support
  • #11004: getWH incorrectly removes padding and border width when box-sizing is border-box
  • #11787: Remove jQuery.curCSS


  • #10589: Remove $.fn.data("events")


  • #11010: Make Deferred.then == Deferred.pipe like Promise/A
  • #11011: Allow traditional options object for $.Callbacks flags
  • #11736: Remove Deferred .isResolved() and .isRejected()
  • #11749: Preserve context objects when multiple Deferred object are passed to $.when()


  • #6724: wrong $(window).height() in mobile safari (iphone)
  • #10877: Make outerWidth/Height a setter
  • #11293: Reading width or outerWidth of empty TDs alters columns width values
  • #11604: Switch $(elem).width(-val) from no-op to $(elem).width(0)
  • #11724: $(document).height() changed in Firefox 12


  • #7109: animate width starts with invalid width on webkit
  • #7157: Animation callback shows element is still ":animated"
  • #8387: flickering problem with jQuery 1.5 hide/show issue with inline and inline-block elements on webkit browsers
  • #8627: .animate() fails on letterSpacing in IE (regression in 1.5.1)
  • #8892: Callback is raised before objects are shown with fadeIn() and jQuery.fx.off = true
  • #9505: animate() issue when mixing percentages and pixels in WebKit
  • #11635: Explicit overflow:auto is overridden by inline overflow:hidden during animation
  • #11755: animate and it aliases should not use :hidden selector
  • #11854: percentage animations jump to end


  • #8545: Leak with events in IE
  • #10067: Firing $.ready on document.readyState === 'interactive' too
  • #11101: Deprecate "exclusive" events option from trigger method
  • #11328: Ctrl key doesn't set event.metaKey to true on Windows
  • #11500: Bug : "change" event handler not executed when triggered manually on IE7 & IE8
  • #11621: Triggering a event on document doesn't bubble to window
  • #11718: Deprecate .data() events
  • #11719: Deprecate .bind("ready") event
  • #11731: Deprecate "hover" pseudo-event
  • #11733: Deprecate .load(), .unload(), and .error() methods
  • #11786: Deprecate .toggle( handler, handler, … ) signature


  • #8894: appendTo() and alike methods called after clone() returns incorrect jQuery set in IE
  • #10324: Clone does not copy innerHTML of object element in IE9
  • #11231: Append, Prepend, After, Before should accept an array as first argument
  • #11338: Inconsistent behavior with .replaceWith() and disconnected nodes.
  • #11566: node.append et al. does not work when node is a DocumentFragment
  • #11617: Define a $.parseHTML method for creating HTML fragments


  • #10996: Simplify offset()
  • #11823: Remove webkitConvertPointFromNodeToPage


  • #3778: selector matching issues
  • #5568: Selectors behave differently with comments tags on FF/IE
  • #8473: In IE9rc *[tabIndex] select all elements without tabindex also
  • #9400: Deprecate :text, :radio, :checkbox, etc. selector extensions
  • #10003: Regression/BC break from #6963
  • #10074: Chaining two [] selector with :first not working
  • #10570: :text selector throws an error in IE7 when there is a cross domain iframe on the page
  • #10697: Sizzle revamp
  • #10809: incorrect test using ".activeElement" in the :focus pseudo-class resolver
  • #11109: Sizzle: Expr.relative truncates prematurely
  • #11814: Sizzle's element-rooted QSA strategy (i.e. attaching a temporary id) does not account for comma and other other selector divisions
  • #11826: Explore a parsed caching system for matchesSelector within Sizzle


  • #9385: Deprecate jQuery.browser
  • #11439: jQuery.support.parentNode used, but not defined any more.
  • #11721: deprecate and remove internal uses of jQuery.support.boxModel
  • #11766: Move jQuery.support to "unstable" status


  • #9800: New method: .addBack (supersedes .andSelf)
  • #11543: .has doesn't work on detached elements
  • #11706: `.has()` fails on document fragments
  • #11738: Remove .closest(Array) returning Array


  • #11325: Improve domManip/buildFragment/clean
  • #11435: Obsolete test code to remove toJSON from .data's return value
  • #11777: Add jQuery Core support for EditorConfig file