This specification defines a means for site developers to programmatically determine the current visibility state of the page in order to develop power and CPU efficient web applications.

Selectors, which are widely used in CSS, are patterns that match against elements in a tree structure [SELECT][CSS21]. The Selectors API specification defines methods for retrieving Element nodes from the DOM by matching against a group of selectors. It is often desirable to perform DOM operations on a specific set of elements in a document. These methods simplify the process of acquiring specific elements, especially compared with the more verbose techniques defined and used in the past.

This document provides an interface for web applications to access timing information related to navigation and elements.

This specification defines an interface that provides the current time in sub-millisecond resolution and such that it is not subject to system clock skew or adjustments.

This document introduces a series of scenarios and a list of requirements guiding the work of the W3C Audio Working Group in its development of a web API for processing and synthesis of audio on the web.

This document captures common practices in designing APIs that fit well into the Web platform as a whole, using WebIDL.

RDFa [RDFA-CORE] enables authors to publish structured information that is both human- and machine-readable. Concepts that have traditionally been difficult for machines to detect, like people, places, events, music, movies, and recipes, are now easily marked up in Web documents. While publishing this data is vital to the growth of Linked Data, using the information to improve the collective utility of the Web for humankind is the true goal. To accomplish this goal, it must be simple for Web developers to extract and utilize structured information from a Web document. This document details such a mechanism; an RDFa Application Programming Interface (RDFa API) that allows simple extraction and usage of structured information from a Web document.

The RDF Interfaces Specification defines a set of standardized interfaces for working with RDF data in a programming environment.

The RDF Application Programming Interface (RDF API) defines a set of standardized interfaces for working with RDF data in a web-based programming environment.

This document describes privacy best practices for web applications, including those that might use device APIs.

These are the requirements intended to be met in the development of client-side APIs that enable the creation of Web Applications and Web Widgets that interact with devices services such as Calendar, Contacts, Camera, etc.

This specification defines low-level events representing points of contact with a touch-sensitive surface.

This specification defines an API for persistent data storage of key-value pair data in Web clients.

This specification defines an application programming interface (API) for widgets that provides, amongst other things, functionality for accessing a widget’s metadata and persistently storing data.

This specification defines HTML form enhancements that provide access to the audio, image and video capture capabilities of the device.

Defines events and interfaces for handling hardware agnostic pointer input from devices such as mouse, pen or touchscreen.

This specification defines an API for opening an HTTP connection for receiving push notifications from a server in the form of DOM events.

This specification defines an API that enables Web pages to use the Web Sockets protocol for two-way communication with a remote host.

This specification defines an interface for web applications to access timing information related to navigation and elements. It is used by other specifications, like User Timing.

This specification defines an interface to help web developers measure the performance of their applications by giving them access to high precision timestamps.

This specification defines an interface for web applications to access timing information related to HTML elements.

This specification defines a new DOM event type that provides information about the battery status of the hosting device and associated auxiliary devices.

An API to control the device's vibrator.

This specification defines an API that allows Web application authors to spawn background workers running scripts in parallel to their main page. This allows for thread-like operation with message-passing as the coordination mechanism.

This specification defines two mechanisms for communicating between browsing contexts in HTML document.

This document defines an interface definition language, Web IDL, that can be used to describe interfaces that are intended to be implemented in web browsers.

This document defines APIs for a database of records holding simple values and hierarchical objects.

An Application Programming Interface and a set of algorithms for programmatically transforming JSON-LD documents in order to make them easier to work with in programming environments like JavaScript, Python, and Ruby.

This specification defines a client-side API to access metadata information related to media resources on the Web.

This specification defines a means to receive events that correspond to a light sensor detecting the presence of a light.

This specification defines a means to receive events that correspond to a proximity sensor detecting the presence of a physical object.

This document defines an API web page authors can use to write script-based animations where the user agent is in control of limiting the update rate of the animation.

This specification defines several new DOM event types that provide information about the physical orientation and motion of a hosting device.

This document defines a set of APIs that allow local media, including audio and video, to be requested from a platform, media to be sent over the network to another browser or device implementing the appropriate set of real-time protocols, and media received from another browser or device to be processed and displayed locally.

This specification defines a System Level API which offers a simple interface to get access to mobile messaging services. A typical use case of the Messaging API is the implementation of a messaging client application that allows the user to send SMS and MMS messages as well as to access and manage the received SMS and MMS messages.

This specification defines the app: URI scheme and rules for dereferencing an app: URI, which can be used to address resources inside a package (e.g., a packaged application). The dereferencing model relies on HTTP semantics to return resources in a manner akin to a HTTP GET request. Doing so allows this URI scheme to be used with other technologies that rely on HTTP responses to function as intended, such as [XHR].

This API provides interfaces to raw UDP sockets, TCP client sockets and TCP server sockets.

This specification extends the HTMLMediaElement interface to provide APIs for controlling playback of protected content

This specification extends the HTMLMediaElement interface to allow JavaScript to generate media streams for playback.

This document describes apis for clipboard operations such as copy/cut and paste, or drag and drop in web applications.

Defines an API that provides Web applications with scripted access to an Input Method Editor

This specification defines a mechanism for an HTML document to discover and subsequently communicate with HTTP-based services advertised via common discovery protocols within a user's network.

This document specifies a runtime and security model for Web Applications. It describes how an application is defined through an application manifest, and how it can be installed, updated and packaged. It also specifies how such an application can be put into the background, be put back in the foreground or woken up. Finally, the document describes the security model for such applications. This includes the permission model and the different security rules that would apply.

This specification defines the WebDriver API, a platform-and language-neutral interface that allows programs or scripts to introspect into, and control the behaviour of, a web browser.

A system level API for managing the user's contacts that are stored in the system's address book.

Defines an API for representing binary data in web applications as a Stream object.

This document defines an API for recording audio and video streams.

This specification defines a System Level API to provide access to the device alarm settings, which can schedule a notification or for an application to be started at a specific time. For example, some applications like alarm-clock, calendar or auto-update might need to utilize Alarm API to trigger particular device behaviors at specified time points.

This document provides an interface for web applications to access timing information related to navigation and elements.

This specification describes a JavaScript API for performing basic cryptographic operations in web applications, such as hashing, signature generation and verification, and encryption and decryption. Additionally, it describes an API for applications to generate and/or manage the keying material necessary to perform these operations. Key storage is provided for both temporary and permanent keys. Access to keying material is contingent on the same origin policy. Uses for this API range from user or service authentication, document or code signing, and the confidentiality and integrity of communications.

This specification describes a high-level JavaScript API for processing and synthesizing audio in web applications. The primary paradigm is of an audio routing graph, where a number of AudioNode objects are connected together to define the overall audio rendering. The actual processing will primarily take place in the underlying implementation (typically optimized Assembly / C / C++ code), but direct JavaScript processing and synthesis is also supported.

The XMLHttpRequest specification defines an API that provides scripted client functionality for transferring data between a client and a server, one of the core components of “AJAX”.

Defines APIs to read screen orientation state and to lock the screen orientation to a specific state.

The Network Information API provides an interface for Web Applications to access the underlying network information (connection info) of the device.

This specification provides an API for representing file objects in web applications, as well as programmatically selecting them and accessing their data.

An API that provides Web applications with scripted access to server-sent application data.

This specification extends the Web Intents service discovery and light-weight RPC mechanism for web applications by defining optional extensions to Web Intents enabled User Agents to discover and dynamically register local Web Intents Services.

This document defines a set of APIs that allow local media, including audio and video, to be requested from a platform, media to be sent over the network to another browser or device implementing the appropriate set of real-time protocols, and media received from another browser or device to be processed and displayed locally.

This specification defines an API that provides access to a user’s unified address book.

The Pick Media Intent defines a Web Intent that enables access to a user's media gallery from inside a Web application. It defines both an Intent action/type pair that selects this operation, and the format of the media data that is returned by services implementing this specification.

This specification defines an API to allow elements to be rendered fullscreen.

API to manage usage and availability of local storage resources

The Selectors API specification defines methods for retrieving Element nodes from the DOM by matching against a group of selectors (as used in CSS).

This specification defines a service discovery and light-weight RPC mechanism for web apps called Web Intents.

This document defines DOM interfaces and markup used by client and service pages to create, receive, and reply to Web Intents messages, and the procedures the User Agent carries out to facilitate that process.

This document defines an API for displaying simple notifications to the user.

Defines a low-level interface that represents gamepad devices.

API that provides scripted access to raw mouse movement data while locking the target of mouse events to a single element and removing the cursor from view.

Defines URL parsing, resolving, and canonicalizing as well as the URL API.

This specification defines an API for writing to files from web applications.

Defines an API to navigate file system hierarchies and sandboxed sections of a user's local filesystem.

This document collates the scenarios that are target use cases for the Media Capture API that enables access to media input capabilities for Web applications using Javascript.

This specification introduces and compares two client-side APIs for processing and synthesizing real-time audio streams in the browser.

This specification defines an API that provides access to messaging functionality in the device, including SMS, MMS and email.

This document identifies the permissions that are needed to use specific client-side APIs which grant access to sensitive data and operations.

This proposal makes HTML Streams the foundation for integrated Web media processing by creating a mixing and effects processing API for HTML Streams.

The Media Capture API enables access to the audio, image and video capture capabilities of the device through Javascript.

This document defines APIs for off-line serving of requests to HTTP resources using static and dynamic responses. It extends the function of application caches defined in HTML5.