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.
TestingWhiz - TestingWhiz is a codeless test automation tool for software, mobile and web.
DalekJS - DalekJS is an open source UI testing tool.
Usetrace - Web app testing system that doesnât require coding or constant updating
Webinject - WebInject is a free tool for automated testing of web applications and web services.
CrossBrowserTesting - Browser Testing made simple! Run automated, visual, and manual tests on 1500+ real browsers and mobile devices. Test more browsers, in less time.