Goto Extensions and search for firebug and do blah blah blah..You will find such thing called firebug.
Firebug and firepath are Add-ons of Firefox ,these does not support any other browser.
Is it verify xpath for IE and Chrome ?
Looking Glass How To Install "Looking Glass" ?
1. Download zip file https://bitbucket.org/primatestinc/looking-glass/downloads/LookingGlass.zip
2. Extract zip file in c driver like "c:\Looking Glass"
3. Double click on 'StartLookingGlass.vbs' to start. (StartLookingGlass.sh for Linux/Mac)
4. If 'Looking Glass' doesn't start, it could be that Java path is not set on your computer, please follow these instructions to set it: https://forums.bukkit.org/threads/how-to-fix-java-is-not-recognized-as-an-internal-command-or-external-command.139263/
5. If you have any concern please visit "https://github.com/dmolchanenko/LookingGlass"