IE 8 Developer Tools
Fiddler is a local proxy server that you need to set your browser to use the local proxy server. Fiddler monitors all browser requests and has the ability to insert data in the browser request. Fiddler supports scripting; a powerful Fiddler script will be very helpful for safety testing.
Take advantage of these debugging tools in the preparation of the XSS payload, and the analysis of browser security will get twice the result with half the effort.