Firefox 13 was shipped on June 5, 2012. This page summarizes the changes in Firefox 13 that affect developers.
Changes for Web developers
cellspacingattributes are now parsed the same outside quirks mode as they are in quirks mode. That is, if a value is specified as a percentage, it's treated as a number of pixels instead, since percentage values are not actually permitted according to the specification.
<wbr>element has seen its bidirectional behavior fixed. It now behaves like the Unicode
ZERO-WIDTH SPACEand therefore doesn't affect bi-directionality of its parent element anymore.
:invalidpseudo-class can now be applied to the
<angle>unit is now supported (to be used with CSS functions like
- Support for 3-to-4 value syntax of the
background-positionhas been added. You can offset a background image from any corner by writing like "
right 10px bottom 20px". See bug 522607
- Support for the 2-value syntax of the CSS
background-repeathas been added.
- Support for
-moz-box-shadowhas been removed. Authors should use unprefixed
box-shadowinstead. See bug 693510
column-fillproperty has been implemented (prefixed).
- Support for the ECMAScript 2015
for..ofconstruct has been added.
- Experimental support for ECMAScript 2015 Map and Set objects has been implemented.
deepargument is now optional, as specified in DOM4.
window.setInterval()methods no longer pass an additional "lateness" argument to the callback routine.
Blob.mozSlice()method has been unprefixed.
- Support for the
Blobconstructor has been added.
- Support for
globalStoragehas been removed.
- The new
DOMRequestinterface, used for reporting the status and result of background operations, has been added.
HTMLOptionElement.index()method now returns
0instead of the incorrect
<option>is inside a
DOMExceptionas defined in DOM Level 4 has been implemented.
FileErrorinterface has been removed in favor of the
DOMErrorinterface as defined in the latest FileAPI specification.
Rangeobject no longer throws a
RangeException. Instead a
DOMExceptionas defined in DOM 4 is used.
element.getAttributeNS()now always returns
nullinstead of the empty string for non-existent attributes. Previously, there were cases in which the empty string could be returned. This is in keeping with the DOM4 specification, which now says this should return null for non-existent attributes, instead of an empty string.
HTMLCanvasElementinterface now has a non-standard
mozFetchAsStream()method, which provides an input stream containing the element's image data in the specified format.
- Firefox for Android now has a Tablet or Mobile token in the UA string to indicate the form factor and no longer has the Fennec token. Also, the number after "Gecko/" is now the Gecko version number instead of a frozen date.
- The UA string no longer exposes the Gecko patch number or release status in the version number; that is, the version number is now always of the form "X.Y", where X is the major release number and Y the minor. For example, "13.0" or "14.1". It will no longer be something like "14.0.1b1".
- Support has been added for the
EXT_texture_filter_anisotropicextension. Anisotropic texture filtering improves the quality of mipmapped texture access when viewing a textured primitive at an oblique angle.
- Support for the
<mtable>elements has been added (bug 722880).
- MathJax fonts are now used as the default fonts for mathematical text. See Fonts for Mozilla's MathML engine for more information.
- The SPDY protocol now enabled by default.
3D view improvements
- You can now press the "f" key to make sure the currently selected node is visible.
Style panel improvements
- Clicking the heading for any rule in the style panel now opens the Style Editor at the corresponding CSS.
- Right-clicking on a rule in the style panel now offers an option to copy the rule to the clipboard.
- Entering an unknown property name, or an illegal property value, displays a warning icon next to that property.
- The Scratchpad now has an option in the Help menu to take you to the MDN documentation about Scratchpad.
Changes for Mozilla and add-on developers
Starting in Firefox 13, Firefox for Windows requires at least Windows XP Service Pack 2; it will no longer run on Windows 2000 or earlier versions of Windows XP.
- Support for a dirty flag has been added to the Source Editor API.
- The Source Editor no longer supports falling back to a
<textarea>instead of using Orion.
- The editor now exposes focus and blur events.
getIndentationString()method has been added; this returns the string to use for indenting text in the editor.
- The Source Editor now supports managing a list of breakpoints and displaying user interface for toggling them on and off; it does not actually implement breakpoints, however. That's up to you to write debugger code for.
- Support has been added for highlighting the current line, using the
- The CSS properties
margin-bottomare now all reflected into ARIA object attributes with the same name. See Gecko object attributes for more information.
nsIScreeninterface now supports controlling rotation through the new
nsIPrefBranch2interface has been merged into
- The new message manager wakeup service, implemented by
nsIMessageWakeupService, has been implemented. See bug 591052.
- The aliases
MozOutlineColor, all of which were removed in previous versions of Gecko, have been removed from
nsIDOMCSS2Properties, which should have been done with the aliases were initially removed.
excludeItemIfParentHasAnnotationhas been removed, along with the corresponding query operation. It existed to support livemarks, which no longer exist.
- Firefox 50 for developers
- Firefox 49 for developers
- Firefox 48 for developers
- Firefox 47 for developers
- Firefox 46 for developers
- Firefox 45 for developers
- Firefox 44 for developers
- Firefox 43 for developers
- Firefox 42 for developers
- Firefox 41 for developers
- Firefox 40 for developers
- Firefox 39 for developers
- Firefox 38 for developers
- Firefox 37 for developers
- Firefox 36 for developers
- Firefox 35 for developers
- Firefox 34 for developers
- Firefox 33 for developers
- Firefox 32 for developers
- Firefox 31 for developers
- Firefox 30 for developers
- Firefox 29 for developers
- Firefox 28 for developers
- Firefox 27 for developers
- Firefox 26 for developers
- Firefox 25 for developers
- Firefox 24 for developers
- Firefox 23 for developers
- Firefox 22 for developers
- Firefox 21 for developers
- Firefox 20 for developers