jQuery — New Wave JavaScript

Meetings are currently held on the matrix.org platform.

Meeting minutes can be found at meetings.jquery.org.

The latest version of jQuery is available at https://jquery.com/download/.

Version support

Version	Branch	Status
4.x	main	Beta
3.x	3.x-stable	Active
2.x	2.x-stable	Inactive
1.x	1.x-stable	Inactive

Once 4.0.0 final is released, the 3.x branch will continue to receive updates for a limited time. The 2.x and 1.x branches are no longer supported.

Commercial support for inactive versions is available from HeroDevs.

Learn more about our version support.

Contribution Guides

In the spirit of open source software development, jQuery always encourages community code contribution. To help you get started and before you jump into writing code, be sure to read these important contribution guidelines thoroughly:

1. Getting Involved
2. Core Style Guide
3. Writing Code for jQuery Projects

References to issues/PRs

GitHub issues/PRs are usually referenced via

, where

NUMBER

is the numerical ID of the issue/PR. You can find such an issue/PR under

https://github.com/jquery/jquery/issues/NUMBER

.

jQuery has used a different bug tracker - based on Trac - in the past, available under bugs.jquery.com. It is being kept in read only mode so that referring to past discussions is possible. When jQuery source references one of those issues, it uses the pattern

, where

NUMBER

is the numerical ID of the issue. You can find such an issue under

https://bugs.jquery.com/ticket/NUMBER

.

Environments in which to use jQuery

• Browser support
• jQuery also supports Node, browser extensions, and other non-browser environments.

What you need to build your own jQuery

To build jQuery, you need to have the latest Node.js/npm and git 1.7 or later. Earlier versions might work, but are not supported.

For Windows, you have to download and install git and Node.js.

macOS users should install Homebrew. Once Homebrew is installed, run

to install git, and

brew install node

to install Node.js.

Linux/BSD users should use their appropriate package managers to install git and Node.js, or build from source if you swing that way. Easy-peasy.

How to build your own jQuery

First, clone the jQuery git repo.

Then, enter the jquery directory, install dependencies, and run the build script:

cd jquery
npm install
npm run build

The built version of jQuery will be placed in the

directory, along with a minified copy and associated map file.

Build all jQuery release files

To build all variants of jQuery, run the following command:

npm run build:all

This will create all of the variants that jQuery includes in a release, including

,

jquery.slim.js

,

jquery.module.js

, and

jquery.slim.module.js

along their associated minified files and sourcemaps.

and

jquery.slim.module.js

are ECMAScript modules that export

jQuery

and

$

as named exports are placed in the

dist-module/

directory rather than the

dist/

directory.

Building a Custom jQuery

The build script can be used to create a custom version of jQuery that includes only the modules you need.

Any module may be excluded except for

. When excluding

selector

, it is not removed but replaced with a small wrapper around native

querySelectorAll

(see below for more information).

Build Script Help

To see the full list of available options for the build script, run the following:

npm run build -- --help

Modules

To exclude a module, pass its path relative to the

folder (without the

.js

extension) to the

--exclude

option. When using the

--include

option, the default includes are dropped and a build is created with only those modules.

Some example modules that can be excluded or included are:

• ajax: All AJAX functionality:

  $.ajax()
  ,
  $.get()
  ,
  $.post()
  ,
  $.ajaxSetup()
  ,
  .load()
  , transports, and ajax event shorthands such as
  .ajaxStart()
  .

• ajax/xhr: The XMLHTTPRequest AJAX transport only.

• ajax/script: The

  <script>
  AJAX transport only; used to retrieve scripts.

• ajax/jsonp: The JSONP AJAX transport only; depends on the ajax/script transport.

• css: The

  .css()
  method. Also removes all modules depending on css (including effects, dimensions, and offset).

• css/showHide: Non-animated

  .show()
  ,
  .hide()
  and
  .toggle()
  ; can be excluded if you use classes or explicit
  .css()
  calls to set the
  display
  property. Also removes the effects module.

• deprecated: Methods documented as deprecated but not yet removed.

• dimensions: The

  .width()
  and
  .height()
  methods, including
  inner-
  and
  outer-
  variations.

• effects: The

  .animate()
  method and its shorthands such as
  .slideUp()
  or
  .hide("slow")
  .

• event: The

  .on()
  and
  .off()
  methods and all event functionality.

• event/trigger: The

  .trigger()
  and
  .triggerHandler()
  methods.

• offset: The

  .offset()
  ,
  .position()
  ,
  .offsetParent()
  ,
  .scrollLeft()
  , and
  .scrollTop()
  methods.

• wrap: The

  .wrap()
  ,
  .wrapAll()
  ,
  .wrapInner()
  , and
  .unwrap()
  methods.

• core/ready: Exclude the ready module if you place your scripts at the end of the body. Any ready callbacks bound with

  jQuery()
  will simply be called immediately. However,
  jQuery(document).ready()
  will not be a function and
  .on("ready", ...)
  or similar will not be triggered.

• deferred: Exclude jQuery.Deferred. This also excludes all modules that rely on Deferred, including ajax, effects, and queue, but replaces core/ready with core/ready-no-deferred.

• exports/global: Exclude the attachment of global jQuery variables ($ and jQuery) to the window.

• exports/amd: Exclude the AMD definition.

• selector: The full jQuery selector engine. When this module is excluded, it is replaced with a rudimentary selector engine based on the browser's

  querySelectorAll
  method that does not support jQuery selector extensions or enhanced semantics. See the selector-native.js file for details.

Note: Excluding the full

module will also exclude all jQuery selector extensions (such as

effects/animatedSelector

and

css/hiddenVisibleSelectors

).

AMD name

You can set the module name for jQuery's AMD definition. By default, it is set to "jquery", which plays nicely with plugins and third-party libraries, but there may be cases where you'd like to change this. Pass it to the

parameter:

npm run build -- --amd="custom-name"

Or, to define anonymously, leave the name blank.

npm run build -- --amd

File name and directory

The default name for the built jQuery file is

; it is placed under the

dist/

directory. It's possible to change the file name using

--filename

and the directory using

--dir

.

--dir

is relative to the project root.

npm run build -- --slim --filename="jquery.slim.js" --dir="/tmp"

This would create a slim version of jQuery and place it under

.

ECMAScript Module (ESM) mode

By default, jQuery generates a regular script JavaScript file. You can also generate an ECMAScript module exporting

as the default export using the

--esm

parameter:

npm run build -- --filename=jquery.module.js --esm

Factory mode

By default, jQuery depends on a global

. For environments that don't have one, you can generate a factory build that exposes a function accepting

window

as a parameter that you can provide externally (see

README

of the published package for usage instructions). You can generate such a factory using the

--factory

parameter:

npm run build -- --filename=jquery.factory.js --factory

This option can be mixed with others like

or

--slim

:

npm run build -- --filename=jquery.factory.slim.module.js --factory --esm --slim --dir="/dist-module"

Custom Build Examples

Create a custom build using

, listing the modules to be excluded. Excluding a top-level module also excludes its corresponding directory of modules.

Exclude all ajax functionality:

npm run build -- --exclude=ajax

Excluding css removes modules depending on CSS: effects, offset, dimensions.

npm run build -- --exclude=css

Exclude a bunch of modules (

is an alias for

--exclude

):

npm run build -- -e ajax/jsonp -e css -e deprecated -e dimensions -e effects -e offset -e wrap

There is a special alias to generate a build with the same configuration as the official jQuery Slim build:

npm run build -- --filename=jquery.slim.js --slim

Or, to create the slim build as an esm module:

npm run build -- --filename=jquery.slim.module.js --slim --esm

Non-official custom builds are not regularly tested. Use them at your own risk.

Running the Unit Tests

Make sure you have the necessary dependencies:

npm install

Start

to auto-build jQuery as you work:

npm start

Run the unit tests with a local server that supports PHP. Ensure that you run the site from the root directory, not the "test" directory. No database is required. Pre-configured php local servers are available for Windows and Mac. Here are some options:

• Windows: WAMP download
• Mac: MAMP download
• Linux: Setting up LAMP
• Mongoose (most platforms)

Essential Git

As the source code is handled by the Git version control system, it's useful to know some features used.

Cleaning

If you want to purge your working directory back to the status of upstream, the following commands can be used (remember everything you've worked on is gone after these):

git reset --hard upstream/main
git clean -fdx

Rebasing

For feature/topic branches, you should always use the

flag to

git pull

, or if you are usually handling many temporary "to be in a github pull request" branches, run the following to automate this:

git config branch.autosetuprebase local

(see

for more information)

Handling merge conflicts

If you're getting merge conflicts when merging, instead of editing the conflicted files manually, you can use the feature

. Even though the default tool

xxdiff

looks awful/old, it's rather useful.

The following are some commands that can be used there:

• Ctrl + Alt + M
  - automerge as much as possible
• b
  - jump to next merge conflict
• s
  - change the order of the conflicted lines
• u
  - undo a merge
• left mouse button
  - mark a block to be the winner
• middle mouse button
  - mark a line to be the winner
• Ctrl + S
  - save
• Ctrl + Q
  - quit

QUnit Reference

Test methods

expect( numAssertions );
stop();
start();

Note: QUnit's eventual addition of an argument to stop/start is ignored in this test suite so that start and stop can be passed as callbacks without worrying about their parameters.

Test assertions

ok( value, [message] );
equal( actual, expected, [message] );
notEqual( actual, expected, [message] );
deepEqual( actual, expected, [message] );
notDeepEqual( actual, expected, [message] );
strictEqual( actual, expected, [message] );
notStrictEqual( actual, expected, [message] );
throws( block, [expected], [message] );

Test Suite Convenience Methods Reference

See test/data/testinit.js.

Returns an array of elements with the given IDs

q( ... );

Example:

q( "main", "foo", "bar" );

=> [ div#main, span#foo, input#bar ]

Asserts that a selection matches the given IDs

t( testName, selector, [ "array", "of", "ids" ] );

Example:

t("Check for something", "//[a]", ["foo", "bar"]);

Fires a native DOM event without going through jQuery

fireNative( node, eventType );

Example:

fireNative( jQuery( "#elem" )[ 0 ], "click" );

Add random number to url to stop caching

url( "some/url" );

Example:

url( "index.html" );

=> "data/index.html?10538358428943"


url( "mock.php?foo=bar" );

=> "data/mock.php?foo=bar&10538358345554"

Run tests in an iframe

Some tests may require a document other than the standard test fixture, and these can be run in a separate iframe. The actual test code and assertions remain in jQuery's main test files; only the minimal test fixture markup and setup code should be placed in the iframe file.

testIframe( testName, fileName,
  function testCallback(
      assert, jQuery, window, document,
	  [ additional args ] ) {
	...
  } );

This loads a page, constructing a url with fileName

. The iframed page determines when the callback occurs in the test by including the "/test/data/iframeTest.js" script and calling

startIframeTest( [ additional args ] )

when appropriate. Often this will be after either document ready or

window.onload

fires.

The

receives the QUnit

assert

object created by

testIframe

for this test, followed by the global

jQuery

,

window

, and

document

from the iframe. If the iframe code passes any arguments to

startIframeTest

, they follow the

document

argument.

Questions?

If you have any questions, please feel free to ask on the Developing jQuery Core forum or in #jquery on libera.