Firefox 16 brings developer command line for faster debugging

Firefox 16 brings developer command line for faster debugging

Summary: The newest version of Firefox includes a command line feature designed to make it easier for developers to debug code and assess websites using the browser's tools.


Mozilla has pushed out Firefox 16, updating the program with a new command line feature designed to tempt developers back to the browser.


The updated browser, released for download on Tuesday, is light on new features in comparison with previous versions, but does introduce a new developer toolbar and the command line.

The developer toolbar, when selected, appears at the bottom of the screen and allows quick access to features like the page inspector and debugger.

Alongside the toolbar is the command line interface: this is designed to allow developers to easily run commands for controlling browser tools, such as style sheets or add-ons, using only the keyboard. For example, typing 'open' prompts the autocomplete to offer the options 'console open' and 'tilt open' (pictured above), while typing 'list' gives the options to jump to the add-on list, break list or cookie list.

In addition, Firefox 16 also "unprefixes a number of stable features including: CSS3 Animations, Transitions, Transforms, Image Values, IndexedDB and Values and Units. Firefox also unprefixes Battery API and Vibration API, two web APIs that Mozilla helped create", Mozilla said in a blog post on Tuesday.

A number of bug fixes have been rolled into Firefox 16, but some known bugs, such as one that causes the browser to crash if it's opened using a locked profile, have not been put right.

The mobile version of the browser has been given minor incremental improvements, including the addition of a 'Reader' mode for viewing and sharing articles on an Android phone or tablet. Tapping the 'reader' button in the Awesome Bar activates the tool, which automatically reformats text and pictures, and removes any ads.

Topics: Browser, Software Development

Ben Woods

About Ben Woods

With several years' experience covering everything in the world of telecoms and mobility, Ben's your man if it involves a smartphone, tablet, laptop, or any other piece of tech small enough to carry around with you.

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  • After having a quick look... this new feature I personally think Mozilla is on the right track but it's not going to be enough.

    For example is you type: edit 2

    It will open a in browser CSS editor with print.css loaded, and focused on line 2. Yes this is slightly faster than trying to find a CSS file than using Chrome Developer Tools, but it's not handy as using inspect element and in Firebug or Chrome Developer Tools and modifying the CSS directly there. This is compounded by the fact that changes to this aren't reflected live on the page...So what is its purpose?

    Personally looking through the list of commands (just type help) there isn't anything there that really jumps out as being "Wow that would save me so much time!".

    Right now I'm going to close Firefox again and probably won't reopen it until I need to do some cross-browser testing.
  • "unprefix"?

    What does "unprefix" mean?
    • Now you mention it, I didn't understand that either!

      Could you enlighten us Ben?