Firefox 19.0: Find out what's new

Martin Brinkmann
Feb 19, 2013
Updated • Feb 19, 2013

Mozilla is preparing to release a new version of the Firefox web browser, Firefox 19.0, today to the public. All other Firefox channels, beta, aurora and nightly, will also receive updates so that their versions move up as well to 20.0, 21.0 and 22.0 respectively.

Firefox 19.0 is already listed on Mozilla's official ftp server and while it is tempting to head right over there to download it, it is recommended to wait until the auto-update feature of the browser picks it up. That is, unless you need to use one of the new or improved features that Mozilla integrated into the new version of the browser, or if you are experiencing issues with an older version of Firefox and want to upgrade to see if they are resolved in the new version.

Firefox 19 What’s New

The main source of information is the beta change log which highlights several important, but not all, changes and improvements in Firefox 19.

Probably the biggest new feature in the new browser version is the new pdf viewer that is integrated into the browser natively. What this means is that you can now display pdf documents in Firefox without having to install a plugin first to do so. This works similar to how it is handled in Google Chrome which also supports the viewing of pdf files natively.

Whenever you click on a pdf document in the browser, it will now be opened directly in it using the built-in reader. You do get options to change that, for instance if you want to use a plugin like that from Adobe Reader instead

A click on open with different viewer opens the pdf document in another program, an installed desktop pdf reader for instance. Controls are displayed on top that you can use to save or print the document, or use other features like zooming in or out, or going directly to a specific page. You can also switch to presentation mode to display the pdf in full screen.

The reader should be sufficient in most situations, and the core benefit here is that users do not have to rely on plugins anymore to view pdf files in the browser directly.So, instead of having to update Adobe Reader or another pdf reader regularly to fix security issues, it is the native reader that can be used instead.

Depending on how you have configured the Firefox browser, telemetry data may be transferred to Mozilla regularly. The new about:telemetry page lists information about the data that is collected and tells you if Telemetry is enabled or not.

The new download panel is still not enabled by default in Firefox 19 but it is likely that this is going to happen in the next major version update. If you are interested in how it looks like do the following:

  1. Type about:config into the address bar of the web browser
  2. Confirm that you will be careful if a warning message is displayed
  3. Search for
  4. Double-click the entry to set it to false

Mozilla has improved the panel again in this release. It is now displaying the download progress of downloads that exceed the three download limit as well (a maximum of three downloads are displayed at any time).

Two improvements have been made to the browser's startup performance which both affect the sequence of events taking place. Firefox previously loaded data before the browser window is shown on the screen. Changes made here improve the startup performance of the browser.

The plugins manager in about:addons is now displaying file names of plugins and plugin MIME types, data that was previously only listed on the about:plugins page.

plugin information screenshot

Web developers benefit from a bunch of new features and improvements:

  • CSS links in the web console now open in the style editor
  • Browser Debugger for add-on and browser developers now available. It is experimental and needs to be enabled by setting to true.
  • The Debugger supports pausing on exceptions and hiding non-enumerable properties.
  • A remote web console is now available to connect to Firefox on Android or Firefox OS. The feature is also experimental and needs to be enabled by setting devtools.debugger.remote-enabled to true.
  • CSS @page, viewport-percentage length units and text-transform full-width are now supported
  • @supports is integrated in Firefox 19 but not activated by default. To enable it, set layout.css.supports-rule.enabled to true.
  • Canvas elements can export their content as an image blob using canvas.toBlob().

Developers may also want to check out Firefox 19 for developers and Site Compatibility for Firefox 19.


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  1. Terrine said on February 21, 2013 at 4:40 pm

    Much niceness. Does anyone know how to hide or disable the “Go to a website” text in the address bar, perhaps using userchrome.css?
    It may be useful for clueless newbies but I really don’t want to see that text for the rest of my life.

  2. Marco said on February 20, 2013 at 1:37 am

    Is it just my impression, or this new version is much faster than the previous ones in terms of pages rendering?

  3. Karl Gephart said on February 19, 2013 at 3:28 pm

    Thanks for clearing up the pdf issue, Martin. You were the only source among many in my reader that went on to explain that the pdf display is native and doesn’t have to depend on Adobe, with all its security vulnerabilities!

    1. Martin Brinkmann said on February 19, 2013 at 4:13 pm

      You are welcome Karl ;)

  4. ilev said on February 19, 2013 at 12:03 pm

    Firefox for Android 19.0 will follow.

  5. Jeanbelga said on February 19, 2013 at 8:26 am

    Thanks for the details.

  6. pd said on February 19, 2013 at 7:08 am


    A remove web console is

    A remote web console is

    Congrats to all on the PDF viewer.

    However attempting to promote a fundamentally late and trivial element of dev tools – clickable styles open the style editor (well, duh!) – as a major feature of a full ‘major’ version number is pathetic. Firebug created this feature well over half a dozen years ago and every browser pretty much copied it since. It should have been the first thing written for the waste-of-resources dev tools. Instead of fixing real bugs like allowing for full styling of a select box, which developers really need right now, Mozilla has wasted time duplicating Firebug.

    1. chris said on February 19, 2013 at 7:56 am

      waaat? you don’t think you can just throw out a statement like that and get away with it, are you?

      Here is styling of the select box, which works fine on firefox

      Here is a chart comparing CSS3 support, which firefox is also doing as good as anybody else,

    2. Martin Brinkmann said on February 19, 2013 at 7:38 am

      Thanks, typo corrected.

  7. ilev said on February 19, 2013 at 5:25 am
  8. Compuitguy said on February 19, 2013 at 4:09 am

    thanks for the news

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