FormVisualizer от tterac

Warning: It is not recommended that you use this extension with your Firefox profile for daily business use. Instead, use this with a profile for testing purpose. This is because you may clear all cookies and local storage data by accident (see feature 2).

You can find source code and license conditions on GitHub.

This extension is designed to make web application security testers' job a little easier. As a pentester, you may sometimes feel annoyed going back and forth between browser and local proxy such as Burp. With this extension, you can do simple request parameter manipulation only inside your browser.

This extension provides following four features:

1. Form visualization and manipulation
You can visualize all form elements (form, input, select, textarea including hidden ones) and others (applet, embed, iframe) in a web page with a single action [Alt+Ctrl+F]. You can easily edit their attributes such as name, value, action, src, method, enctype, target and disabled. The screen shots show how this feature looks like. This extension provides context menu to see and manipulate link URLs as well.

2. Clearing cookie, local storage and cache
You can clear all cookies and local storage data with a single action [Alt+Ctrl+D].
Additionally, browsing cache can be cleared from menu button.
Be aware that no confirmation screen is show upon deletion.

3. Show DOM HTML source.
This shows DOM HTML source (i.e. document.documentElement.outerHTML) with a single action [Alt+Ctrl+S]. The source is syntax highlighted.

4. Track HTTP response status code and URLs.
This shows HTTP status code in the top right corner of the browser tab.
Only HTTP status code of top-level navigation is shown.
From v1.3.2, URLs fetched by the page (top-level navigation, iframe, XHR, websocket etc.) are shown in developer tool console.