files/en-us/mozilla/firefox/releases/35/index.md
Firefox 35 was released on January 13th, 2015. 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:
All devtools bugs fixed between Firefox 34 and Firefox 35.
-moz-appearance with the none value on a combobox now remove the dropdown button (Firefox bug 649849).element.style["css-property-name"] has been added to match other browsers (Firefox bug 958887).bottommargin, leftmargin, rightmargin and topmargin attributes of the {{HTMLElement("body")}} element have been activated in non-quirks mode (Firefox bug 95530).The "temporal dead zone" for let declarations has been implemented. In conformance with ES2015 let semantics, the following situations now throw errors. See also this newsgroup announcement and Firefox bug 1001090.
let within the same scope in function bodies is now a syntax error.let in function bodies before the declaration is reached and evaluated is now a runtime error.ES2015 {{jsxref("Global_Objects/Symbol", "Symbols")}} (only available in the Nightly channel) have been updated to conform with recent specification changes:
String(Symbol("1")) now no longer throws a {{jsxref("TypeError")}}; instead a string ("Symbol(1)") gets returned (Firefox bug 1058396).The various TypedArray constructors now have as their [[Prototype]] a single function, denoted %TypedArray% in ES2015 (but otherwise not directly exposed). Each typed array prototype now inherits from %TypedArray%.prototype. (%TypedArray% and %TypedArray%.prototype inherit from Function.prototype and Object.prototype, respectively, so that typed array constructors and instances still have the properties found on those objects.) Typed array function properties now reside on %TypedArray%.prototype and work on any typed array. See TypedArray and Firefox bug 896116 for more information.
ES2015 semantics for prototype mutations using object literals have been implemented (Firefox bug 1061853).
__proto__:value will mutate the [[Prototype]] in the object literal syntax.__proto__() {} will not overwrite the [[Prototype]] anymore.canvas.filters.enabled flag (Firefox bug 927892).Animation.target property. This always is behind the dom.animations-api.core.enabled pref, off by default (Firefox bug 1067701).crossOrigin reflected attribute of {{domxref("HTMLImageElement")}}, {{domxref("HTMLLinkElement")}}, {{domxref("HTMLMediaElement")}}, {{domxref("HTMLScriptElement")}}, and {{domxref("SVGScriptElement")}} only accepts valid values, and "" isn't, null has to be used instead (Firefox bug 880997).null anymore (Firefox bug 1068058).200 in case of success (instead of the erroneous 0) (Firefox bug 716491).'#xyz') of the URL, if relevant (Firefox bug 1073882).File.mozFullPath property is no more visible from content (Firefox bug 1048293).AbortablePromise, a promise that can be aborted by a different entity that the one who created it, has been added. It is prefixed with Moz and controlled by the dom.abortablepromise.enabled property, defaulting to false (Firefox bug 1035060).Navigator.mozIsLocallyAvailable property has been removed (Firefox bug 1066826).network.websocket.enabled, true by default, has been removed; WebSocket API cannot be deactivated anymore (Firefox bug 1091016).dtls OpenType feature (via the CSS {{cssxref("font-feature-settings")}} on the default stylesheet) is now applied automatically to MathML elements when positioning scripts over it (e.g., dotless i with mathematical hat).No change.
No change.
alt-svc header is now supported (Firefox bug 1003448).base-uri directive is now supported (Firefox bug 1045897)._getTabForBrowser() method on the <xul:tabbrowser> element has been deprecated. In its place, we've added a new, public, method called getTabForBrowser. This returns, predictably, the <xul:tab> element that contains the specified <xul:browser>.Components.utils.now(), matching {{domxref("Performance.now()")}} has been implemented for non-window chrome code (Firefox bug 969490).isPrivateBrowsing from BrowserWindow.toJSON method to URL instances.GitHub commits made between Firefox 34 and Firefox 35. This will not include any uplifts made after this release entered Aurora.
Bugs fixed between Firefox 34 and Firefox 35. This will not include any uplifts made after this release entered Aurora.