Mozilla has launched a new feature with Firefox 16 called the Developer Toolbar, which comes with what Mozilla calls the Developer Command Line. This is designed to provide easy keyboard control over Firefox developer tools, and it completes commands and parameters for you.
"In addition, Firefox unprefixes a number of stable features including: CSS3 Animations, Transitions, Transforms, Image Values, IndexedDB and Values and Units," Mozilla says in a blog post. "Firefox also unprefixes Battery API and Vibration API, two Web APIs that Mozilla helped create."
"On mobile, Firefox for Android introduces Reader Mode to make it easier to view, read and share articles and stories from your mobile phone or tablet," Mozilla adds. "Simply tap the 'Reader' icon in the Awesome Bar to activate. This feature provides an enjoyable and clutter-free way to read online content by removing advertisements, reformatting pictures and increasing font size."
The toolbar will also show you the errors on a page if there are any. It displays an error indicator next to the web console.
Simply press shift+F2 to bring the toolbar up.