If (like me) you have to support JavaScript on IE7 and IE8 then you'll know what a royal pain in the ass it is to debug. Today I found this excellent app that removes that pain proper breakpoint support, stepping, etc. Don't let the horrendously 1990s looking web site put you off, the app works great and has saved me loads of time already! http://www.remotedebugger.com/javascript_debugger/javascript_debugger.asp