Array.prototype.find

The `find()` method returns the value of the first item in the array based on the result of the provided testing function.

Array.prototype.findIndex

The `findIndex()` method returns the index of the first element in the array that satisfies the provided testing function.

flat & flatMap array methods

Methods to flatten any sub-arrays found in an array by concatenating their elements.

Array.prototype.includes

Determines whether or not an array includes the given value, returning a boolean value (unlike `indexOf`).

Asynchronous Clipboard API

A modern, asynchronous Clipboard API based on Promises

Async functions

Async functions make it possible to treat functions returning Promise objects as if they were synchronous.

background-position-x & background-position-y

CSS longhand properties to define x or y positions separately.

Battery Status API

Method to provide information about the battery status of the hosting device.

Web Cryptography

JavaScript API for performing basic cryptographic operations in web applications

CSS :any-link selector

The `:any-link` CSS pseudo-class matches all elements that match `:link` or `:visited`

CSS Filter Effects

Method of applying filter effects using the `filter` property to elements, matching filters available in SVG. Filter functions include blur, brightness, contrast, drop-shadow, grayscale, hue-rotate, invert, opacity, sepia and saturate.

CSS Hyphenation

Method of controlling when words at the end of lines should be hyphenated using the "hyphens" property.

CSS3 Opacity

Method of setting the transparency level of an element

Encrypted Media Extensions

The EncryptedMediaExtenstions API provides interfaces for controlling the playback of content which is subject to a DRM scheme.

Filesystem & FileWriter API

Method of reading and writing files to a sandboxed file system.

CSS Flexible Box Layout Module

Method of positioning elements in horizontal or vertical stacks. Support includes all properties prefixed with `flex`, as well as `display: flex`, `display: inline-flex`, `align-content`, `align-items`, `align-self`, `justify-content` and `order`.

KeyboardEvent.charCode

A legacy `KeyboardEvent` property that gives the Unicode codepoint number of a character key pressed during a `keypress` event.

KeyboardEvent.code

A `KeyboardEvent` property representing the physical key that was pressed, ignoring the keyboard layout and ignoring whether any modifier keys were active.

KeyboardEvent.getModifierState()

`KeyboardEvent` method that returns the state (whether the key is pressed/locked or not) of the given modifier key.

KeyboardEvent.key

A `KeyboardEvent` property whose value is a string identifying the key that was pressed. Covers character keys, non-character keys (e.g. arrow keys), and dead keys.

KeyboardEvent.location

A `KeyboardEvent` property that indicates the location of the key on the input device. Useful when there are more than one physical key for the same logical key (e.g. left or right "Control" key; main or numpad "1" key).

KeyboardEvent.which

A legacy `KeyboardEvent` property that is equivalent to either `KeyboardEvent.keyCode` or `KeyboardEvent.charCode` depending on whether the key is alphanumeric.

Payment Request API

Payment Request is a new API for the open web that makes checkout flows easier, faster and consistent on shopping sites.

HTTP Public Key Pinning

Declare that a website's HTTPS certificate should only be treated as valid if the public key is contained in a list specified over HTTP to prevent MITM attacks that use valid CA-issued certificates.

readonly attribute of input and textarea elements

Makes the form control non-editable. Unlike the `disabled` attribute, `readonly` form controls are still included in form submissions and the user can still select (but not edit) their value text.

Ruby annotation

Method of adding pronunciation or other annotations using ruby elements (primarily used in East Asian typography).

Efficient Script Yielding: setImmediate()

Yields control flow without the minimum delays enforced by setTimeout

Typed Arrays

JavaScript typed arrays provide a mechanism for accessing raw binary data much more efficiently. Includes: `Int8Array`, `Uint8Array`, `Uint8ClampedArray`, `Int16Array`, `Uint16Array`, `Int32Array`, `Uint32Array`, `Float32Array` & `Float64Array`

accelerometer api: y

cssrotate api: y

cssscale api: y

csstranslate api: y

dompoint api: y

domrect api: y

magnetometer api: y

mouseevent api: y

svgpoint api: y

svgrect api: y

svgsvgelement api: y

svguseelement api: y

webkitpoint api: y

xrviewport api: y

css property: y

svg element: line: y1

svg element: line: y2

svg element: mask: y

svg element: rect: y

svg element: svg: y

svg element: text: y

svg element: use: y