May I know?

Informative article about IE9 based web sites: http://blogs.msdn.com/b/ie/archive/2010/09/13/interoperable-html-parsing-in-ie9.aspx

All modern browsers support JavaScript 1.5 at the least, most supporting 1.6 to 1.8. That's not quite helpful enough though. To get the exact version, you could test for a single new feature in each version. How can you do this? Create a test page to test the JavaScript version, and run it on the Android browser. JavaScript 1.6 has a bunch of new Array functions. 1.7 introduces Iterator objects. JavaScript 1.8 introduces the reduce Array function. So we can test for these: var jsVersion = 1.5; if (([]).forEach) jsVersion = 1.6; if (window.Iterator) jsVersion = 1.7; if (([]).reduce) jsVersion = 1.8; http://efreedom.com/Question/1-3510767/Javascript-Version-Android