Addons useful for coding and otherwise developing websites
The Web Developer extension adds various web developer tools to the browser.
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
FontFinder is created for designers, developers and typographers. It allows a user to analyze the font information of any element on a page, copy any piece(s) of that information to the clipboard, and perform inline replacements to test new layouts.
CodeBurner is a Firefox add-on that integrates with Firebug, to extend it with reference material for HTML and CSS.
Open With Photoshop is a new companion for web and graphic designers to open up any web image with Adobe Photoshop via a single and quick mouse click.
Stop searching at PHP.net to simply remember some function signature. With this addon you can search functions quickly for the official function description directly into your browser without a new tab.
Plus, many tools to help PHP developers.
Browser pixel rulers to help inspect window widths of adaptive designs. The add-on button acts as a toggle that adds rulers similar to a graphics app to measure the current window resolution.
A suite of tools for developers.