JsUnit is a Unit Testing framework for client-side (in-browser) JavaScript. It is essentially a port of JUnit to JavaScript. Also included is a platform for automating the execution of tests on multiple browsers and mutiple machines running different OSs.
Crosscheck is a unit-testing library and framework for javascript. It emulates the execution environment normally provided by a web browser enabling developers to quickly and easily test their code in a variety of environments. Browser environments from all platforms and all vendors can be emulated with Crosscheck.