I am looking for a tool (preferably a plugin to Firefox) that will show and parse all the JS in a page as I browse.


Most tools focus on the HTML parser. I need good js parsing e.g. list of all JS functions in a webpage, with includes...

Try Firebug on this link http://www.google-analytics.com/ga.js and you get sore eyes.


Firebug or Chrome Developer Tools is probably your best bet.

Chrome Developer Tools has a "pretty print" feature that allows you to deobfuscate JavaScript code, making it easier to read. You can get the same feature in Firebug by installing the JavaScript Deminifier extension, or you can just use JSBeautifier if you want to deobfuscate an individual JavaScript file.

When debugging in either Firebug or Chrome Dev Tools, you can see a list of all JavaScript variables and functions available within the local or global scope. In Chrome, you can even edit the JavaScript dynamically. Last year's Google I/O presentation explains how to use Chrome to debug JavaScript.

If your end goal is to read through or understand a piece of JavaScript, something like JSBeautifier should suffice, perhaps in addition to jsFiddle if you want to do some testing. Otherwise, if your goal is to understand JavaScript within the context of a website, using Firebug or Chrome Dev Tools to set breakpoints and step through the JavaScript code should work well. I personally use both when perusing JavaScript files in web apps, and they both have suited my needs just fine.

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