Actually it is very easy to debug any javascript error. In IE there is a setting where you can uncheck the Disable Script debugging (Internet Explorer) and in the status bar you will see any javascript error. If you check the checkbox IE will not report any errors. In general during your development you should always uncheck the box.If you double click the javascript status this will exactly report the line number where the javscript error is. I exactly don't know if you see these kind of errors in Chrome and firefox. I know people blame IE but there are quite few nice handy features which are very helpful during development