September 2015 web platform update

Newly available on the web platform
Newly available

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.
Flexbox: Flexbox is a one-dimensional layout system, which places content either horizontally or vertically, with optional wrapping. Learn more.
HTTP/2: The HTTP/2 protocol is a major revision of the HTTP network protocol, providing improved performance and efficiency by using a single TCP connection to send multiple streams of data at once. Learn more.
2D transforms: The transform CSS property and its 2D transform functions allow rotating, scaling, skewing, and translating an element. Arbitrary 2D transforms are also possible using a transformation matrix. 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.from(): The Array.from() and typed array .from() static methods copy items from an iterable or array-like object to make a new array. Learn more.
Array.of(): The Array.of() and typed array .of() static methods create new arrays from the values of any number of arguments. Learn more.
Typed array iteration methods: Typed array iteration methods 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.from(): The Array.from() and typed array .from() static methods copy items from an iterable or array-like object to make a new array. Learn more.
Typed array iteration methods: Typed array iteration methods Learn more.

font-synthesis: The font-synthesis CSS shorthand property disables all font synthesis except the given kinds. To disable a specific kind of font synthesis, instead use the longhand properties such as font-synthesis-style and font-synthesis-weight. Learn more.
:nth-child() of <selector>: The of syntax for the :nth-child() and :nth-last-child() CSS functional pseudo-classes match elements by the relative position of elements, counted from the first or last sibling matching a selector list. Learn more.

font-synthesis: The font-synthesis CSS shorthand property disables all font synthesis except the given kinds. To disable a specific kind of font synthesis, instead use the longhand properties such as font-synthesis-style and font-synthesis-weight. Learn more.
:nth-child() of <selector>: The of syntax for the :nth-child() and :nth-last-child() CSS functional pseudo-classes match elements by the relative position of elements, counted from the first or last sibling matching a selector list. Learn more.