Firefox

Strict & highly optimizable subset of JavaScript that can be used as low-level compile target.

Provides one-off and periodic synchronization for Service Workers with an onsync event.

Allows real-time video capture of the surface of the canvas.

A way to define and use variables that can be used in place of any CSS property.

Determines how a font face is displayed based on whether and when it is downloaded and ready to use.

Wrap document content around non-rectangular shapes, or constrain content to a holding shape.

Define a custom HTML tag and associate it with an ES6 class.

Provides access to device's physical orientation.

Low level API for fetching network resources that is more powerful and flexible than XMLHttpRequest.

Provides an easy way for web content to be presented using the user's entire screen.

Access and respond to signals from gamepads and other game controllers.

A two-dimensional grid-based layout system, optimized for user interface design.

Include reusable HTML documents in other HTML documents

Declared fragments of markup which are parsed as HTML, implicitly inactive until instantiated later on at runtime.

Creates a Blob object representing a file containing the image in a canvas.

Next revision of the HTTP protocol for faster transport of web content.

An asynchronous client-side storage API offering fast access to large amounts of structured data

Encode audio and video streams in the browser.

Allows creating media streams via JavaScript and play them using <audio> and <video> elements.

Render canvas contexts (WebGL or Canvas2D) from a web worker.

Programmatically determine the visibility state of a page, and to be notified if the visibility state changes.

API to register event listeners that explicitly cannot prevent the default action of the event.

Provides a consistent programmatic way to query the status of API permissions attributed to the current context.

Requests permission to use a given API.

Revokes the permission currently set on a given API.

Handle hardware agnostic pointer input from devices including mouse, pen, touchscreen, etc..

Access to raw mouse movement, locks the target of mouse events to a single element, eliminates limits of how far mouse movement can go in a single direction, and removes the cursor from view.

The Promise object is used for deferred and asynchronous computations.

Receive messages pushed to the client from a server even when the site isn't focused or even open in the user-agent.

Request a callback when the user agent is idle. With requestIdleCallback web developers will be able to schedule background computation tasks on the event loop that has a better chance of not interfering with other more time-critical operations.

Allows reading to the current screen orientations, getting events on orientation changes and locking orientation state.

Event-driven scripts that can handle network requests and manage cached responses in the background.

Provides encapsulation for JavaScript, CSS, and templating in a Web Component.

Fine-grained borrowing and sharing for ArrayBuffer between workers.

A specific kind of worker that can be accessed from several browsing contexts, such as several windows, iframes or even workers.

Representing and handling a stream of data in JavaScript.

integrity attributes for scripts and stylesheets to protect against unexpected modifications.

Access to vibration hardware, allowing physical feedback to the user by causing the device to shake.

Create and manage animations run by the browser. (Detailed Firefox implementation status)

JSON-based manifest that provides developers with a centralized place to put metadata associated with a web application.

High-level JavaScript API for processing and synthesizing audio in web applications.

An API for communicating with Bluetooth Low Energy devices as a GATT Client.

Javascript API to recognize speech input in web applications.

Javascript API to generate text-to-speech output in web applications.

WebAssembly is a low-level, portable, size- and load-time-efficient binary code format; designed to serve as a compilation target for the web.

An API closely conforming to OpenGL ES 2.0 for rendering 3D and 2D graphics in a <canvas> element.

An update to WebGL, based on OpenGL ES 3.0.

Capture and stream audio, video, and arbitrary data between browsers without requiring an intermediary.

Allows creating and managing a WebSocket connection to a server, as well as sending and receiving data on the connection.