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jQuery - New Wave JavaScript

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. Tips For Bug Patching

What you need to build your own jQuery

In order to build jQuery, you need to have GNU make 3.8 or later, Node.js/npm latest, and git 1.7 or later. (Earlier versions might work OK, but are not tested.)

Windows users have two options:

  1. Install msysgit (Full installer for official Git), GNU make for Windows, and a binary version of Node.js. Make sure all three packages are installed to the same location (by default, this is C:\Program Files\Git).
  2. Install Cygwin (make sure you install the git, make, and which packages), then either follow the Node.js build instructions or install the binary version of Node.js.

Mac OS users should install Xcode (comes on your Mac OS install DVD, or downloadable from Apple's Xcode site) and Once Homebrew is installed, run brew install git to install git, and brew install node to install Node.js.

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

How to build your own jQuery

First, clone a copy of the main jQuery git repo by running:

git clone git://

Enter the directory and install the node dependencies:

cd jquery && npm install

Make sure you have grunt installed by testing:

grunt -version

Then, to get a complete, minified (w/ Ugligy.js), linted (w/ JSHint) version of jQuery, type the following:


The built version of jQuery will be put in the dist/ subdirectory.

Running the Unit Tests

Start grunt to auto-build jQuery as you work:

cd jquery && grunt watch

Run the unit tests with a local server that supports PHP. No database is required. Pre-configured php local servers are available for Windows and Mac. Here are some options:

Building to a different directory

If you want to build jQuery to a directory that is different from the default location:

grunt && grunt dist:/Users/you/Dropbox/Public/

With this example, the output files would be:


Git for dummies

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


The repository uses submodules, which normally are handled directly by the Makefile, but sometimes you want to be able to work with them manually.

Following are the steps to manually get the submodules:

  1. git clone
  2. git submodule init
  3. git submodule update


  1. git clone
  2. git submodule update --init


  1. git clone --recursive

If you want to work inside a submodule, it is possible, but first you need to checkout a branch:

  1. cd src/sizzle
  2. git checkout master

After you've committed your changes to the submodule, you'll update the jquery project to point to the new commit, but remember to push the submodule changes before pushing the new jquery commit:

  1. cd src/sizzle
  2. git push origin master
  3. cd ..
  4. git add src/sizzle
  5. git commit

The makefile has some targets to simplify submodule handling:

make update_submodules

checks out the commit pointed to by jquery, but merges your local changes, if any. This target is executed when you are doing a normal make.

make pull_submodules

updates the content of the submodules to what is probably the latest upstream code.

make pull

make a make pull_submodules and after that a git pull. if you have no remote tracking in your master branch, you can execute this command as make pull REMOTE=origin BRANCH=master instead.


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):

  1. git reset --hard upstream/master
  2. git clean -fdx


For feature/topic branches, you should always used 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 (see 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 an 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 );
    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] );
raises( 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 id="main">, <span id="foo">, input id="bar">]

Asserts that a selection matches the given IDs

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

@example t("Check for something", "//[a]", ["foo", "baar"]);

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.php" );

@example url("data/test.html") => "data/test.html?10538358428943"

@example url("data/test.php?foo=bar") => "data/test.php?foo=bar&10538358345554"

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.

testIframe( fileName, testName, callback );

Callback arguments:

callback( jQueryFromIFrame, iFrameWindow, iFrameDocument )

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

testIframeWithCallback( testName, fileName, callback )


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

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