Possible Duplicate:
capturing javascript error in selenium
can we capture/automate the js errors thrown in browser while clicking the page .Is it possible to capture with selenium (as far my knowledge i think no!)
Well I'll repost it here again. You can do it by handling window.onerror
event. See the following link http://www.silverwareconsulting.com/index.cfm/2010/6/7/Checking-for-JavaScript-Errors-with-Selenium. But anyway, this question is possibly duplicate with this one.