This extension has a 4.5 star rating with no complaints to see in the reviews. It has been around for years and is loved by many. This is the developers website. Please donate if you can't live without this extension. http://chrispederick.com/work/web-developer/The Web Developer extension adds various web developer tools to a browser. The extension is available for Chrome and Firefox, and will run on any platform that these browsers support including Windows, OS X and Linux.