Persistence allows Microsoft Internet Explorer 5 and later to retain Web page information, styles, variables, and state. For example, a collapsible list of links within a table of contents can remain expanded to the user's choice upon leaving and later returning to the page. Or, a search engine query form can retain the last-used search string. Persistence is implemented as a behavior .
Persistence creates new opportunities for the author.
Information that persists beyond a single page without support from the server, or within the finite scope of cookies , can increase the speed of navigation and content authoring. These behaviors can be used to preserve information in the browser's history, in favorites, in an XML store, or directly within a Web page saved to disk. When a user returns to a persisted page, the state of the page can be restored. By allowing information to safely reside on the client, fewer server transactions are required. Custom start pages and Web applications will prosper because information can continue to exist without the paternal support of the server, or repeated server queries.