files/en-us/mozilla/firefox/releases/13/index.md
Firefox 13 was shipped on June 5, 2012. This page summarizes the changes in Firefox 13 that affect developers.
cellspacing attributes 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.U+200B ZERO-WIDTH SPACE and therefore doesn't affect bi-directionality of its parent element anymore.turn {{cssxref("<angle>")}} unit is now supported (to be used with CSS functions like rotate()).right 10px bottom 20px. See Firefox bug 522607border-radius or box-shadow instead. See Firefox bug 693510for...of construct has been added.deep argument is now optional, as specified in DOM4.globalStorage has been removed.DOMRequest interface, used for reporting the status and result of background operations, has been added.0 instead of the incorrect -1 when the {{HTMLElement("option")}} is inside a {{HTMLElement("datalist")}} HTML element.FileError interface has been removed in favor of the {{domxref("DOMError")}} interface as defined in the latest FileAPI specification.RangeException. Instead a {{domxref("DOMException")}} as defined in DOM 4 is used.null instead 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.mozFetchAsStream() method, which provides an input stream containing the element's image data in the specified format.Array (see Firefox bug 722071).EXT_texture_filter_anisotropic extension. Anisotropic texture filtering improves the quality of mipmapped texture access when viewing a textured primitive at an oblique angle.width attribute on {{MathMLElement("mtable")}} elements has been added (Firefox bug 722880).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.
getIndentationString() method has been added; this returns the string to use for indenting text in the editor.highlightCurrentLine configuration option.nsIScreen interface now supports controlling rotation through the new rotation attribute.nsIPrefBranch2 interface has been merged into nsIPrefBranch (Firefox bug 718255).nsIMessageWakeupService, has been implemented. See Firefox bug 591052.MozOpacity, MozOutline, MozOutlineStyle, MozOutlineWidth, MozOutlineOffset, and 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.nsINavHistoryQueryOptions attribute excludeItemIfParentHasAnnotation has been removed, along with the corresponding query operation. It existed to support livemarks, which no longer exist.