Developer Tools in Internet Explorer 8
As you probably heard, IE8 introduces the Developer Tools. Lots of great features like live HTML and CSS editing, JScript debugging and profiler, HTML, CSS validators.
More information: https://blogs.msdn.com/ie/archive/2008/09/03/developer-tools-in-internet-explorer-8-beta-2.aspx
But also:
https://msdn.microsoft.com/en-us/library/cc848894(VS.85).aspx - Discovering the Internet Explorer 8 Developer Tools
https://msdn.microsoft.com/en-us/library/cc848892(VS.85).aspx - Developer Tools: Script Debugging Overview
https://msdn.microsoft.com/en-us/library/cc848893(VS.85).aspx - Internet Explorer 8 Developer Tools GUI Reference
https://msdn.microsoft.com/en-us/library/cc848895(VS.85).aspx - Developer Tools: Script Profiler Overview
https://msdn.microsoft.com/en-us/library/cc848896(VS.85).aspx - Developer Tools: Keyboard Shortcuts
Currently in Beta 2, the build can be downloaded and tested from: https://www.microsoft.com/windows/internet-explorer/beta/worldwide-sites.aspx.