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

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:

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

In order to build jQuery, you need to have GNU make 3.8 or later, Node.js 0.4.12 or later, 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 http://mxcl.github.com/homebrew/. 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.

First, clone a copy of the main jQuery git repo by running git clone git://github.com/jquery/jquery.git.

Then, to get a complete, minified, jslinted version of jQuery, simply cd to the jquery directory and type make. If you don't have Node installed and/or want to make a basic, uncompressed, unlinted version of jQuery, use make jquery instead of make.

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

To remove all built files, run make clean.

If you want to build jQuery to a directory that is different from the default location, you can specify the PREFIX directory: make PREFIX=/home/jquery/test/ [command]

With this example, the output files would end up in /home/jquery/test/dist/.

Sometimes, the various git repositories get into an inconsistent state where builds don't complete properly (usually this results in the jquery.js or jquery.min.js being 0 bytes). If this happens, run make clean, then run make again.

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 https://github.com/jquery/jquery.git
2. git submodule init
3. git submodule update

Or:

1. git clone https://github.com/jquery/jquery.git
2. git submodule update --init

Or:

1. git clone --recursive https://github.com/jquery/jquery.git

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:

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.

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

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)

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

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