files/en-us/mozilla/firefox/releases/33/index.md
Firefox 33 was released on October 14, 2014. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
Highlights
For details please see the hacks post. Special thanks to the 33 contributors that added all the features and fixes in this release.
ethiopic-numeric, persian, arabic-indic, devanagari, bengali, gurmukhi, gujarati, oriya, tamil, telugu, kannada, malayalam, thai, lao, myanmar, khmer, cjk-heavenly-stem, cjk-earthly-branch in {{cssxref("list-style-type")}} (Firefox bug 985825 and Firefox bug 1063856).mongolian, disclosure-open and disclosure-closed counter styles in {{cssxref("list-style-type")}} (Firefox bug 982355 and Firefox bug 1063856).rebeccapurple, a new {{cssxref("<color>")}} name defined in CSS Colors level 4 (Firefox bug 1024642).layout.css.font-features.enabled preference, enabled by default in Nightly. Newly implemented features are:
Added the experimental support for {{htmlelement("picture")}} element (Firefox bug 870022), behind the dom.image.picture.enabled preference (off by default).
The {{HTMLElement("label")}}, especially without a for attribute, doesn't apply anymore to a <input type=hidden> field (Firefox bug 597650). The previous behavior wasn't spec-compliant.
The link annotation noreferrer has been implemented on {{HTMLElement("a")}} elements. <a rel="noreferrer"> will not include the URL of the referrer in the HTTP request sent to fetch it (Firefox bug 530396). Note that this works only for in-page links, not for links clicked via the UI, like via contextual menus.
On Android, support for two new values for the name attribute of {{HTMLElement("meta")}} has been added: msapplication-TileImage and msapplication-TileColor (Firefox bug 1014712). Example:
<meta name="msapplication-TileImage" content="images/my-img-144.png" />
<meta name="msapplication-TileColor" content="#d83434" />
Number.toInteger() has been removed (Firefox bug 1022396).undefined (Firefox bug 1031632).function f(x, y) { return {x, y}; } is equivalent to function f(x, y) { return {x: x, y: y}; } (Firefox bug 875002).yield and yield* has been updated to conform with the latest ES2015 specification (Firefox bug 981599).hasOwn trap has been removed (Firefox bug 980565).DOMException.stack property has been added. It returns a string with a human-friendly formatted stack (Firefox bug 857648), in the same format as the existing non-standard {{jsxref("Error.stack")}} property.media.mediasource.enabled preference, enabled by default in Nightly and Aurora only, now supports MP4 (Firefox bug 1000686).media.track.enabled, off by default (Firefox bug 744896).XMLHttpRequest.mozBackgroundRequest() is no more accessible from websites. Only Firefox-internal code (Chrome code) can use it (Firefox bug 1035242).touchenter and touchleave events, removed from the specification, have been removed (Firefox bug 1036444).loaded event, sent on a {{domxref("HTMLTrackElement")}} has been renamed {{domxref("Window/load_event", "load")}} to match the specification (Firefox bug 1035505).FileHandle has been renamed in IDBMutableFile (Firefox bug 1006485).LockedFile has been renamed in IDBFileHandle (Firefox bug 1006485).dom.serviceWorkers.enabled flag (Firefox bug 903441)."unknown" value (Firefox bug 1023029).columnspacing, framespacing, and rowspacing of the {{MathMLElement("mtable")}} element are now supported (Firefox bug 330964).No change.
RTCOfferOptions dictionary, used to provide options when calling {{domxref("RTCPeerConnection.createOffer()")}}, has been implemented.frame-ancestors directive is now supported (Firefox bug 846978).Panel constructor.tab.readyState.BrowserWindow parameter to sidebar.show() and sidebar.hide(), to control the window for which the sidebar will be shown or hidden.GitHub commits made between Firefox 32 and Firefox 33. This will not include any uplifts made after this release entered Aurora.
Bugs fixed between Firefox 32 and Firefox 33. This will not include any uplifts made after this release entered Aurora.