The jQuery Validation Plugin provides drop-in validation for your existing forms, while making all kinds of customizations to fit your application really easy.

If you've wrote custom methods that you'd like to contribute to additional-methods.js, create a branch, add the method there and send a pull request for that branch.

If you've wrote a patch for some bug listed on http://plugins.jquery.com/project/issues/validate, please provide a link to that issue in your commit message.