Beginning in Safari 3.1 and iPhone OS 2.0, Safari supports the HTML5 JavaScript database class. The JavaScript database class, based on SQLite, provides a very basic relational database intended for local storage of content that is too large to conveniently store in cookies (or is too important to accidentally delete when the user clears out his or her cookies).
Because it provides a relational database model, the JavaScript database class makes it easy to work with complex, interconnected data in a webpage. You might use it as an alternative to storing user-generated data on the server (in a text editor, for example), or you might use it as a high-speed local cache of information the user has recently queried from a server-side database.
