Find out the current light level or illuminance of the ambient light around the user's device.

Find out how quickly or slowly a physical device is moving across the x, y, and z axes when a user moves it.

The USB interface of the WebUSB API provides attributes and methods for finding and connecting USB devices from a web page.

A special format for transcripts and captioning of videos.

Enable live streaming and real-time communication of media between browsers.

Render high-performance interactive 3D and 2D graphics within any compatible web browser without the use of plug-ins.

The Notifications API allows web pages to control the display of system notifications to the end user. These are outside the top-level browsing context viewport, so therefore can be displayed even when the user has switched tabs or moved to a different app. The API is designed to be compatible with existing notification systems, across different platforms.

Play audio, add effects to audio, create audio visualizations, apply spatial effects (such as panning) and much more.

Control how animations are presented and created on the fly - great for allowing the user to adjust animation settings for accessibility.

Provide physical feedback to the user by causing the device to shake.

Change and manipulate the browser URL.

Interpret finger (or stylus) activity on touch screens or trackpads.

Prevent devices from dimming or locking the screen when an application needs to keep running.

Create screenshots and screencasts from your web app!

Find out how long it takes to load a specific resource, such as an XMLHttpRequest, SVG, image, or script.

Like media queries, but for individual elements instead of the entire viewport size. Get information when an element on the page has resized.

The Push API gives web applications the ability to receive messages pushed to them from a server, whether or not the web app is in the foreground, or even currently loaded. This lets developers deliver asynchronous notifications and updates to users that opt in, resulting in better engagement with timely new content.

Detect when a user is close to a device. These events make it possible to react to such a change, for example by shutting down the screen of a smartphone when the user is having a phone call with the device close to their ear.

Add support for styluses and other types of user pointing/input deviced besides a mouse, including detecting of tilt.

The Picture-in-Picture API allow websites to create a floating video window always on top of other windows so that users may continue consuming media while they interact with other content sites, or applications on their device.

A way for users to select their preferred way of paying for things, and make that information available to a merchant.

Find out what kind of internet connection your website visitor is using - celluar, wifi, etc. This can be used to select high definition content or low definition content based on the user's connection.

The Navigation Timing API provides data that can be used to measure the performance of a web site, including how quickly or slowly something loads.

Find out what tasks on your page, including style changes or events in your JavaScript, take 50 milliseconds or more.

Find out when an element on the page is visible, passes a certain point on the page, or intersects with something else on the page

Find out when a user has a browser tab focused, or has switched to another tab

The MediaStream Image Capture API is an API for capturing images or videos from a photographic device. In addition to capturing data, it also allows you to retrieve information about device capabilities such as image size, red-eye reduction and whether or not there is a flash and what they are currently set to. Conversely, the API allows the capabilities to be configured within the constraints what the device allows.

HTML Drag and Drop interfaces enable applications to use drag-and-drop features in browsers.

The Gamepad API is a way for developers to access and respond to signals from gamepads and other game controllers in a simple, consistent way. It contains three interfaces, two events and one specialist function, to respond to gamepads being connected and disconnected, and to access other information about the gamepads themselves, and what buttons and other controls are currently being pressed.

The Fullscreen API adds methods to present a specific Element (and its descendants) in full-screen mode, and to exit full-screen mode once it is no longer needed. This makes it possible to present desired content—such as an online game—using the user's entire screen, removing all browser user interface elements and other applications from the screen until full-screen mode is shut off.