One of the biggest challenges of many enterprise web applications is the support on the different browsers with different versions. JavaScript code that runs on Safari does not necessarily mean it will work on IE or Firefox or Google chrome. This challenge is inherited from the lack of testing the JavaScript code that lives in the presentation tier from day one. Without unit testing the JavaScript code, organization will pay much money for testing, re-testing, and re-testing web applications for just deciding upgrading or supporting new browsers.