TamperData

TamperData is an extension for Mozilla Firefox. You can use TamperData to halt the traffic http requests that are processing and to "Tamper", change, modify any of the data that is being submitted to the website.

TamperData is easily installed within your Firefox browser and is extremely easy to use. It only takes a moment to install and become familiar with the way it works.

The one thing that I haven't figured out to do with TamperData, is to modify HTTP GET parameters, I can see how to modify the HTTP headers, post parameters, but the GET parameters are a bit more misleading to me.

All in all TamperData is an easy, excellent way to see what your web application is doing, and start testing with different and various other types of data. Parameter manipulation is very easy to do, there is no need to use Javascript Injection or re-posting web pages. This is a much easier way to just tamper with the data as it is being submitted to the web application.

TamperData