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:
Environments in which to use jQuery
- Browser support differs between the master (2.x) branch and the 1.x-master branch. Specifically, 2.x does not support legacy browsers such as IE6-8. The jQuery team continues to provide support for legacy browsers on the 1.x-master branch. Use the latest 1.x release if support for those browsers is required. See browser support for more info.
- To use jQuery in Node, browser extensions, and other non-browser environments, use only 2.x releases. 1.x does not support these environments.
What you need to build your own jQuery
In order to build jQuery, you need to have Node.js/npm latest and git 1.7 or later. (Earlier versions might work OK, but are not tested.)
Mac OS users should install Homebrew. Once Homebrew is installed, run
brew install git to install git,
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
Clone a copy of the main jQuery git repo by running:
git clone git://github.com/jquery/jquery.git
Enter the jquery directory and run the build script:
cd jquery && npm run build
The built version of jQuery will be put in the
dist/ subdirectory, along with the minified copy and associated map file.
If you want create custom build or help with jQuery development, it would be better to install grunt command line interface as a global package:
npm install -g grunt-cli
Make sure you have
grunt installed by testing:
Now by running
grunt command, in the jquery directory, you could build full version of jQuery, just like with
npm run build command:
There are many other tasks available for jQuery Core:
Special builds can be created that exclude subsets of jQuery functionality.
This allows for smaller custom builds when the builder is certain that those parts of jQuery are not being used.
For example, an app that only used JSONP for
$.ajax() and did not need to calculate offsets or positions of elements could exclude the offset and ajax/xhr modules.
Any module may be excluded except for
selector. To exclude a module, pass its path relative to the
src folder (without the
Some example modules that can be excluded are:
- ajax: All AJAX functionality:
.load(), transports, and ajax event shorthands such as
- ajax/xhr: The XMLHTTPRequest AJAX transport only.
- ajax/script: The
<script>AJAX transport only; used to retrieve scripts.
- ajax/jsonp: The JSONP AJAX transport only; depends on the ajax/script transport.
- css: The
.css()method plus non-animated
.toggle(). Also removes all modules depending on css (including effects, dimensions, and offset).
- deprecated: Methods documented as deprecated but not yet removed; currently only
- dimensions: The
- effects: The
.animate()method and its shorthands such as
- event: The
.off()methods and all event functionality. Also removes
- event/alias: All event attaching/triggering shorthands like
- offset: The
- wrap: The
- core/ready: Exclude the ready module if you place your scripts at the end of the body. Any ready callbacks bound with
jQuery()will simply be called immediately. However,
jQuery(document).ready()will not be a function and
.on("ready", ...)or similar will not be triggered.
- deferred: Exclude jQuery.Deferred. This also removes jQuery.Callbacks. Note that modules that depend on jQuery.Deferred(AJAX, effects, core/ready) will not be removed and will still expect jQuery.Deferred to be there. Include your own jQuery.Deferred implementation or exclude those modules as well (
- exports/global: Exclude the attachment of global jQuery variables ($ and jQuery) to the window.
- exports/amd: Exclude the AMD definition.
As a special case, you may also replace Sizzle by using a special flag
- sizzle: The Sizzle selector engine. When this module is excluded, it is replaced by a rudimentary selector engine based on the browser's
querySelectorAllmethod that does not support jQuery selector extensions or enhanced semantics. See the selector-native.js file for details.
Note: Excluding Sizzle will also exclude all jQuery selector extensions (such as
The build process shows a message for each dependent module it excludes or includes.
As an option, 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. Simply set the
grunt custom --amd="custom-name"
Or, to define anonymously, set the name to an empty string.
grunt custom --amd=""
Custom Build Examples
To create a custom build of the latest stable version, first check out the version:
git pull; git checkout $(git describe --abbrev=0 --tags)
Then, make sure all Node dependencies are installed:
Create the custom build using the
grunt custom option, listing the modules to be excluded.
Exclude all ajax functionality:
Excluding css removes modules depending on CSS: effects, offset, dimensions.
Exclude a bunch of modules:
For questions or requests regarding custom builds, please start a thread on the Developing jQuery Core section of the forum. Due to the combinatorics and custom nature of these builds, they are not regularly tested in jQuery's unit test process. The non-Sizzle selector engine currently does not pass unit tests because it is missing too much essential functionality.
Running the Unit Tests
Make sure you have the necessary dependencies:
grunt watch or
npm start to auto-build jQuery as you work:
cd jquery && grunt watch
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:
Building to a different directory
To copy the built jQuery files from
/dist to another directory:
grunt && grunt dist:/path/to/special/location/
With this example, the output files would be:
To add a permanent copy destination, create a file in
dist/ called ".destination.json". Inside the file, paste and customize the following:
Additionally, both methods can be combined.
As the source code is handled by the Git version control system, it's useful to know some features used.
If you want to purge your working directory back to the status of upstream, following commands can be used (remember everything you've worked on is gone after these):
git reset --hard upstream/mastergit clean -fdx
For feature/topic branches, you should always use the
--rebase flag to
git pull, or if you are usually handling many temporary "to be in a github pull request" branches, run following to automate this:
git config branch.autosetuprebase local
man git-config 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
git mergetool. Even though the default tool
xxdiff looks awful/old, it's rather useful.
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
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
Returns an array of elements with the given IDs
;div#main span#foo input#bar
Asserts that a selection matches the given IDs
Fires a native DOM event without going through jQuery
Add random number to url to stop caching
Load tests in an iframe
Loads a given page constructing a url with fileName:
"./data/" + fileName + ".html"
and fires the given callback on jQuery ready (using the jQuery loading from that page)
and passes the iFrame's jQuery to the callback.
Load tests in an iframe (window.iframeCallback)
Loads a given page constructing a url with fileName:
"./data/" + fileName + ".html"
The given callback is fired when window.iframeCallback is called by the page.
The arguments passed to the callback are the same as the
arguments passed to window.iframeCallback, whatever that may be
If you have any questions, please feel free to ask on the Developing jQuery Core forum or in #jquery on irc.freenode.net.