Do you work a lot with JavaScript and need to unit test your JavaScript code? You want to look into QUnit.
QUnit is a powerful, easy-to-use JavaScript until test framework that allows developers to test JavaScript code. QUnit is used by the jQuery, jQuery UI, and jQuery Mobile projects.
QUnit was originally developed by John Resig as part of jQuery. In 2008 it got its own home, name and API documentation, allowing others to use it for their unit testing as well. At the time it still depended on jQuery. A rewrite in 2009 fixed that, and now QUnit runs completely standalone.