files/en-us/mozilla/firefox/releases/26/index.md
Firefox 26 was released on December 10, 2013. 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.
'blink' as a valid value, though it doesn't blink the content at all (Firefox bug 812995).-moz-text-blink property has been removed (Firefox bug 812995).from-image keyword and EXIF support, has been added (Firefox bug 825771).position: sticky has been implemented and can be enabled by pref layout.css.sticky.enabled (Firefox bug 886646).::-moz-placeholder pseudo-element (Firefox bug 915551).HTMLSelectElement.selectedOptions property has been implemented (Firefox bug 596681).email, values with domain labels longer than 63 chars are no more considered valid (Firefox bug 884332).HTMLInputElement.width and height properties now return 0 when the type is not image (Firefox bug 905240).ECMAScript 2015 implementation continues!
{ value: foo, done: bool } (Firefox bug 907744).Math: Math.fround() (Firefox bug 900125).SyntaxError (Firefox bug 907958).function f(x=1, y). See Firefox bug 777060.URLUtils mixin: {{domxref("URL")}}, {{domxref("Location")}}, {{domxref("HTMLAnchorElement")}}, and {{domxref("HTMLAreaElement")}} (Firefox bug 887364).<profile>/indexedDB to <profile>/storage/persistent (on b2g from /data/local/indexedDB to /data/local/storage/persistent).default value, mapping to portrait-primary or landscape-primary, depending of the device (Firefox bug 908058) This works only for Firefox OS and Firefox for Android. Firefox Desktop is not supported.sandbox attribute now throws a security error (Firefox bug 907892).initMessageEvent method has been removed while the interface has now a constructor (Firefox bug 848294).MessageChannel API has been implemented, behind the dom.messageChannel.enabled preference (Firefox bug 677638).VTTCue, behind the media.webvtt.enabled preference, like for all WebVTT-related implementations, has been added (Firefox bug 868509).SVGElement.ownerSVGElement() method doesn't throw anymore (Firefox bug 835048).