CSS element() function

This function renders a live image generated from an arbitrary HTML element

CSS Environment Variables env()

Usage of environment variables like `safe-area-inset-top`.

CSS Exclusions Level 1

Exclusions defines how inline content flows around elements. It extends the content wrapping ability of floats to any block-level element.

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.

Media Queries: interaction media features

Allows a media query to be set based on the presence and accuracy of the user's pointing device, and whether they have the ability to hover over elements on the page. This includes the `pointer`, `any-pointer`, `hover`, and `any-hover` media features.

CSS :read-only and :read-write selectors

:read-only and :read-write pseudo-classes to match elements which are considered user-alterable

Element.closest()

DOM method that returns the current element if it matches the given selector, or else the closest ancestor element that matches the given selector, or else null.

document.elementFromPoint()

Given coordinates for a point relative to the viewport, returns the element that a click event would be dispatched at if the user were to click the point (in other words, the element that hit-testing would find).

Scroll methods on elements (scroll, scrollTo, scrollBy)

Methods to change the scroll position of an element. Similar to setting `scrollTop` & `scrollLeft` properties, but also allows options to be passed to define the scroll behavior.

Encrypted Media Extensions

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

ECMAScript 5

Full support for the ECMAScript 5 specification. Features include `Function.prototype.bind`, Array methods like `indexOf`, `forEach`, `map` & `filter`, Object methods like `defineProperty`, `create` & `keys`, the `trim` method on Strings and many more.

ECMAScript 2015 (ES6)

Support for the ECMAScript 2015 specification. Features include Promises, Modules, Classes, Template Literals, Arrow Functions, Let and Const, Default Parameters, Generators, Destructuring Assignment, Rest & Spread, Map/Set & WeakMap/WeakSet and many more.

ES6 classes

ES6 classes are syntactical sugar to provide a much simpler and clearer syntax to create objects and deal with inheritance.

ES6 Generators

ES6 Generators are special functions that can be used to control the iteration behavior of a loop. Generators are defined using a `function*` declaration.

JavaScript modules via script tag

Loading JavaScript module scripts (aka ES6 modules) using `<script type="module">` Includes support for the `nomodule` attribute.

JavaScript modules: dynamic import()

Loading JavaScript modules dynamically using the import() syntax

ES6 Number

Extensions to the `Number` built-in object in ES6, including constant properties `EPSILON`, `MIN_SAFE_INTEGER`, and `MAX_SAFE_INTEGER`, and methods ` isFinite`, `isInteger`, `isSafeInteger`, and `isNaN`.

String.prototype.includes

The includes() method determines whether one string may be found within another string, returning true or false as appropriate.

Server-sent events

Method of continuously sending data from a server to the browser, rather than repeatedly requesting it (EventSource interface, used to fall under HTML5)

ui-serif, ui-sans-serif, ui-monospace and ui-rounded values for font-family

Allows more control when choosing system interface fonts

Fetch

A modern replacement for XMLHttpRequest.

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`.

Intrinsic & Extrinsic Sizing

Allows for the heights and widths to be specified in intrinsic values using the `max-content`, `min-content`, `fit-content` and `stretch` (formerly `fill`) properties.

Object.entries

The `Object.entries()` method creates a multi-dimensional array of key value pairs from the given object.

String.prototype.padStart(), String.prototype.padEnd()

The `padStart()` and `padEnd()` methods pad the current string with a given string (eventually repeated) so that the resulting string reaches a given length. The pad is applied from the start (left) of the current string for `padStart()`, and applied from the end (right) of the current string for `padEnd()`.

Rest parameters

Allows representation of an indefinite number of arguments as an array.

Web Animations API

Lets you create animations that are run in the browser, as well as inspect and manipulate animations created through declarative means like CSS.

Web Bluetooth

Allows web sites to communicate over GATT with nearby user-selected Bluetooth devices in a secure and privacy-preserving way.

Web Authentication API

The Web Authentication API is an extension of the Credential Management API that enables strong authentication with public key cryptography, enabling password-less authentication and / or secure second-factor authentication without SMS texts.

WebGL 2.0

Next version of WebGL. Based on OpenGL ES 3.0.

entrysync api

ext_srgb api

javascript built-in: error

javascript built-in: error: `error()` constructor

javascript built-in: error: tostring

javascript built-in: eval

javascript built-in: math: e

javascript built-in: math: exp

javascript built-in: math: expm1

javascript built-in: string: endswith

emoji support

ecmascript 3

ecmascript 2016 (es7)

ecmascript 4