In one of projects we use extensive amounts of javascripts to modify HTML on runtime. It is very difficult to troubleshoot ex: when an user says we see a small white color shade on the right side of the screen whatever code we check in visual studio will not provide an answer.
Now comes a tool that helps it is call IE Developer ToolBar from Microsoft- http://www.microsoft.com/downloadS/details.aspx?familyid=E59C3964-672D-4511-BB3E-2D5E1DB91038&displaylang=en
good tool to help and increase your productivity. Thanks