Well, download Fiddler first by visiting http://www.fiddler2.com/fiddler2/version.asp.
Everyone loves BeyondCompare, isn't it?. At least, it's my favourite comparison tool. I know the tool and feels comfortable with it.
To set it on Fiddler, open QuickExce box by pressing alt + q. Then type the following commands there. The path to BC can be different depending on your installation. (from fiddler's CompareTool help)
[sourcecode language="bash"]<br>about:config<br>PREFS SET fiddler.config.path.differ "C:\Program Files (x86)\Beyond Compare 3\BComp.com"<br>PREFS SET fiddler.differ.Params "/diff \"{0}\" \"{1}\""<br>[/sourcecode]
Now, when you select two web sessions and press ctrl + w, you can compare those sessions against each other on beyond
It's a text editor that helps you edit script rules and offers syntax highlighting and a class explorer (really useful) to help you author scripts. Get the installer with screenshot from FiddlerScript page.
Before you start installation, you need close your Fiddler.
With script editor, you can add a custom column.
https://gist.github.com/3171042
I love keyboard shortcuts.