Firefox 20

  1. Firefox 20 Download
  2. Firefox 2000

A faster, more secure and customizable Web browser.

Mozilla Firefox (64-bit) - Mozilla Firefox is a fast, light and tidy open source web browser. At its public launch in 2004 Mozilla Firefox was the first browser to challenge Microsoft Internet Explorer’s dominance. Since then, Mozilla Firefox has consistently featured in the top 3 most popular browsers globally and this is set to continue thanks to the release of Firefox 30. The key features that have made Mozilla Firefox so popular are the simple and effective UI, browser speed and strong security capabilities. The browser is particularly popular with developers thanks to its open source development and active community of advanced users.

50 million more phones. On the mobile side, Firefox 20 for Android supports private browsing on a per-tab basis, Mozilla said, giving users a way to open a new private browsing tab during their. Firefox is a small, fast and very easy to use browser that offers many advantages over other web browsers, such as the ability to block pop-up windows and the tabbed browsing. Reviews and ratings for Beyond 20. Find out what other users think about Beyond 20 and add it to your Firefox Browser.

Mozilla Firefox is a free and open-source web browser developed for Windows, OS X, and Linux, with a mobile version for Android. Firefox 3.6 Release Notes. V.3.6.20, released August 16th, 2011 Check out what’s new, the known issues and frequently asked questions about the latest version of Firefox.

Easier Browsing

Mozilla put of a lot of resources into creating a simple but effective UI aimed at making browsing quicker and easier. They created the tab structure that has been adopted by most other browsers. In recent years Mozilla has also focused on maximizing browsing area by simplifying toolbar controls to just a Firefox button (which contains settings and options) and back/forward buttons. The URL box features direct Google searching as well as an auto predict/history feature called Awesome Bar. On the right side of the URL box there are bookmarking, history and refresh buttons. To the right of the URL box is a search box which allows you to customize your search engine options. Outside of that a view button controls what you see below the URL. Next to that you have the download history and home buttons.


Mozilla Firefox boasts impressive page load speeds thanks to the excellent JagerMonkey JavaScript engine. Start up speed and graphics rendering are also among the quickest in the market. Firefox manages complex video and web content using layer-based Direct2D and Driect3D graphics systems. Crash protection ensures only the plugin causing the issue stops working, not the rest of the content being browsed. Reloading the page restarts any affected plugins. The tab system and Awesome Bar have been streamlined to launch/get results very quickly too.


Firefox was the first browser to introduce a private browsing feature which allows you to use the internet more anonymously and securely. History, searches, passwords, downloads, cookies and cached content are all removed on shutdown. Minimizing the chances of another user stealing your identity or finding confidential information. Content security, anti-phishing technology and antivirus/antimalware integration ensures your browsing experience is as safe as possible.

Firefox 20

Personalisation & Development

One of the best features of the Firefox UI is customization. Simply right click on the navigation toolbar to customize individual components or just drag and drop items you want to move around. The inbuilt Firefox Add-ons Manager allows you to discover and install add-ons within the browser as well as view ratings, recommendations and descriptions. Read about the top recommended add-ons for Mozilla Firefox on TechBeat. Thousands of customizable themes allow you to customize the look and feel of your browser. Site authors and developers can create advanced content and applications using Mozilla’s open source platform and enhanced API.

  • Firefox keeps getting faster as a result of significant updates to SpiderMonkey, our JavaScript engine, you will now experience improved page load performance by up to 15%, page responsiveness by up to 12%, and reduced memory usage by up to 8%. We have replaced part of the JavaScript engine that helps to compile and display websites for you, improving security and maintainability of the engine at the same time.
  • Firefox introduces HTTPS-Only Mode. When enabled, this new mode ensures that every connection Firefox makes to the web is secure and alerts you when a secure connection is not available. You can enable it in Firefox Preferences.
  • Pinch zooming will now be supported for our users with Windows touchscreen devices and touchpads on Mac devices. Firefox users may now use pinch to zoom on touch-capable devices to zoom in and out of webpages.
  • Picture-in-Picture now supports keyboard shortcuts for fast forwarding and rewinding videos: use the arrow keys to move forward and back 15 seconds, along with volume controls.
  • When you are presenting your screen on a video conference in Firefox, you will see our improved user interface that makes it clearer which devices or displays are being shared.
  • Firefox supports AcroForm, which will allow you to fill in, print, and save supported PDF forms and the PDF viewer also has a new fresh look.
  • Selecting a search engine at the bottom of the search panel now enters search mode for that engine, allowing you to see suggestions (if available) for your search terms. The old behavior (immediately performing a search) is available with a shift-click.
  • When Firefox autocompletes the URL of one of your search engines, you can now search with that engine directly in the address bar by selecting the shortcut in the address bar results.
  • We have added buttons at the bottom of the search panel to allow you to search your bookmarks, open tabs, and history.
  • Our users in India on the English build of Firefox will now see Pocket recommendations in their new tab featuring some of the best stories on the web.
Firefox 20
Windows 7/8/10/8.1
Flock delivers the latest webmail, photos, videos and updates from your favorites sites.
Surf the Web and customize your browsing experience.
Surf the Internet via browser with innovative dual-core design that uses both Webkit and Trident.
A faster, more secure and customizable Web browser.
Innovative new features improve the way you view the web.
Navigate the Internet using browser with powerful search, sharing, and multimedia capabilities.
Explore the Web with optimized built-in smart tools for secured, ad-free browsing.

Firefox 20 was released on . This article provides information about the changes in this release that will affect developers.

Changes for Web developers


  • Support for the download attribute on the <a> and <area> element has been added (bug 676619).
  • The value auto for the global attributedir has been implemented (bug 548206).
  • The global attributecontextmenu now works on Firefox for Android (bug 736321).


  • Support for the Weakmap.prototype.clear() method, recently added to the Harmony (EcmaScript 2015) draft proposal has been added (bug 814562).
  • Support for the Math.imul() method, a C-style 32-bit multiplication function. Though proposed for Harmony (EcmaScript 2015) it has not yet accepted and still is non-standard (bug 808148).
  • Web apps using draggable text with Kinetic 3.x are working, even when using the Cairo canvas backend (bug 835064).
  • The for each…in statement has been deprecated and should not be used. Consider using the new for…of statement (bug 804834).
  • Support for the Map.prototype.keys(), Map.prototype.values(), and Map.prototype.entries() has been added (bug 817368).


  • CSS Flexbox is now available by default in pre-release builds only (excluding beta versions). It can be enabled in release and beta version by setting the layout.css.flexbox.enabled about:config preference to true.
  • The mask-type property from the CSS Masking specification has been added (bug 793617).
  • Experimental support for the :scope pseudo-class has been added. Enabled by default in Aurora and Nightly, it can be enabled in release and beta version by setting the layout.css.scope-pseudo.enabled about:config preference to true (bug 648722).


  • HTMLMediaElement supports now playbackRate (both read and write), with pitch correction. Pitch correction can be controlled using the property mozPreservesPitch (bug 495040).
  • CSSOM: Support for the new CSSGroupingRule and CSSConditionRule has been added (bug 814907).
  • CSSOM: On CSSRule the constant CSSRule.MOZ_KEYFRAME_RULE and CSSRule.MOZ_KEYFRAMES_RULE have been unprefixed to CSSRule.KEYFRAME_RULE and CSSRule.KEYFRAMES_RULE. The prefixed version are temporarily kept for helping Web author to transition their code bug 816431).
  • CSSOM: It is now possible to set the value of conditionText for CSSMediaRule (bug 815021).
  • The DOMParserparseFromStream and parseFromBuffer methods are no longer available from web content (bug 816410).
  • The XMLSerializerserializeToStream method is no longer available from web content (bug 816410).
  • TextDecoder and TextEncoder interfaces are now available in Workers (bug 795542).
  • Support for the CSS.supports() method has been added, behind the layout.css.supports-rule.enabled pref (off by default) (bug 779917).
  • Support for UndoManager has been added (bug 617532).
  • The CSSOM Document.caretPositionFromPoint() method, which returns a CaretPosition has been implemented.
  • The index argument of the tableRow.insertCell and table.insertRow methods has been made optional as per HTML specification.
  • Navigator.getUserMedia, still prefixed as Navigator.mozGetUserMedia is now activated by default.
  • The third, optional, transfer argument of Window.postMessage is now supported. It allows to transfer a sequence of Transferable objects to the destination (bug 822094).
  • The non-standard Window.sizeToContent() method now clamps the minimal size: the window cannot be forced anymore to small sizes preventing the user to interact with (bug 764240).
  • Blend modes, such as overlay, color-burn, hue, etc. have been added to the Canvas CanvasRenderingContext2D.globalCompositeOperation property (bug 748433).
  • The prefixed version of window.indexedDBwindow.mozIndexedDB — was reintroduced to Gecko, so that bad cross-browser prefixing code (such as var indexedDB = window.indexedDB window.webkitIndexedDB ...) doesn't break in Firefox. A better approach is window.indexedDB = window.indexedDB window.webkitIndexedDB ... (see bug 770844.)


  • The implementation of the contentScriptType and contentStyleType properties has been removed from SVGSVGElement along with the removal from SVG2 (bug 819731).


Firefox 20 Download

  • To help MathML authors debugging 'invalid-markup' errors in their documents, MathML parsing errors (such as having too many / too few child elements) and warnings about deprecated attributes or wrong attribute values are now reported to the Error Console.
  • The scriptminsize attribute now accepts unitless values and percent values. They are interpreted as multiples of the default value ('8pt').
  • Unitless values are now also allowed for the mathsize and fontsize attributes; they multiply the default value.

Changes for add-on and Mozilla developers

  • ECMAScript for XML (E4X) is now fully disabled for all chrome and content scripts. It was previously disabled for content in Firefox 17 and has been removed entirely for Firefox 21. Use DOMParser/DOMSerializer or a non-native JXON algorithm instead.
  • The nsIDOMParserJS interface no longer exists bug 816410. See nsIDOMParser for alternatives.
  • Content Preferences: The nsIContentPrefService interface is now deprecated and the asynchronous nsIContentPrefService2 storage API has been implemented.
  • The nsIProfile and nsIProfileChangeStatus interfaces have been removed, along with other code supporting the pre-Firefox profile management system. You probably weren't using these interfaces, but if you were, you should stop doing so. This prevents defunct parts of the profile management system from vetoing the shutdown process.
  • The nsIEventSource interface no longer exists bug 819639.

See also

Firefox 2000

Older versions