In addition to the chrome.* APIs, extensions can use all the APIs that the browser provides to web pages and apps. If the browser doesn't support an API you want to use, you can bundle additional API libraries into your extension.

Here's a sampling of the APIs that extensions can use:

Standard JavaScript APIs

[PENDING: define, explain; link to complete list]

XMLHttpRequest

Lets the extension request data from one or more servers. The manifest specifies which domains the extension can send requests to. [PENDING: link to doc]

WebKit APIs

Because Google Chrome is built upon WebKit, your extensions can use WebKit APIs. Especially useful are the experimental CSS features such as filters, animations, and transformations. Here's an example of using WebKit styles to make the UI spin:

<style>
  div:hover {
    -webkit-transform: rotate(360deg);
    -webkit-transition: all sl ease-out;
  }
</style>

[PENDING: link to complete list of webkit apis]

V8 APIs, such as JSON

JSON is in V8, so you don't need to include a JSON library to use JSON functions. [PENDING: what other APIs are in v8? link to complete list]

HTML5 APIs, such as localStorage and Web Workers

HTML5 is still being defined and implemented, but one crucial feature it will provide is local storage... [PENDING: mention Web Workers, too. Other important API? link to complete list]

APIs in bundled libraries

If you want to use a library that the browser doesn't provide (for example, jQuery), you can bundle that library's JavaScript files with your extension. Bundled libraries work in extensions just as they would in any other web pages.