September 2014 web platform update

Now available in Chrome Android
Limited availability

<dialog>: The <dialog> HTML element represents a modal or non-modal dialog box, such as a confirmation prompt or a subwindow used to enter data. Learn more.
Pointer lock: Provides access to raw mouse movement by locking the target of mouse events to a single element and hiding the mouse cursor. Learn more.

Array copyWithin(): The copyWithin() method of arrays and typed arrays shifts or copies items of an array to another index of the array without changing its length. Learn more.

Array copyWithin(): The copyWithin() method of arrays and typed arrays shifts or copies items of an array to another index of the array without changing its length. Learn more.

Array fill(): The fill() method of arrays and typed arrays sets all or some items of an array to a given a value. Learn more.
Array find() and findIndex(): The find() and findIndex() methods of arrays and typed arrays search an array for the first item that satisfies a test function. Learn more.
Audio and video tracks: The audioTracks and videoTracks APIs for media elements switch audio and video tracks during playback. Learn more.
fastSeek(): The fastSeek() method seeks an <audio> or <video> element as fast as possible, by seeking to a keyframe instead of exactly the requested time. Learn more.
Map (initial support): Map objects hold key-value pairs and remember the original insertion order of the keys. Learn more.
Promise (initial support): A promise represents an asynchronous operation which eventually succeeds or fails. Learn more.
Set (initial support): Set objects store unique values of any type. Learn more.
<template>: The <template> HTML element holds HTML fragments which you can clone and insert into the document using JavaScript. Learn more.
WebVTT: WebVTT is a captions and subtitles format. WebVTT files are loaded using the <track> element, and the VTTCue API can be used to create or update cues dynamically. Learn more.