Selenium - Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that.
httest - The httest provides a large variety of HTTP-related functionality, useful for implementing all...
DalekJS - DalekJS is an open source UI testing tool.
Webinject - WebInject is a free tool for automated testing of web applications and web services.
UI.Vision - Modern open-source task and test automation tool and Selenium IDE.
Watir - Watir stands for Web Application Testing In Ruby. It facilitates the writing of automated tests by mimicking the behavior of a user interacting with a website. CommunityWatir stands for Web Application Testing In Ruby.