Scripting APIs in HTML 5
A two-dimensional drawing API that can be used on a new canvas (Canvas) element to render images, game graphics, or other running visual graphics.
An API that allows Web applications to register themselves as a protocol or MIME type.
An API that introduces a new caching mechanism to support offline Web applications.
An API that can play video and audio, using new videos and audio elements.
A history API that exposes the history that is being browsed, allowing the page to better support the fallback functionality in AJAX applications.
Cross-document messaging, which provides a way for documents to communicate with each other without regard to their source domain, and to some extent this is designed to prevent Cross-site scripting attacks.
An API that supports drag-and-drop operations, which can be associated with the draggable attribute.
An API that supports editing operations that can be associated with a new global contenteditable attribute.
A new network API that enables Web applications to communicate with each other on the local network and maintain two-way communication on their source servers.
The event sent by the server, which can be associated with the new event source (Event-source) element, the new event source element facilitates a persistent connection to the remote data source, and greatly eliminates the need for polling in the Web application.