Server Push

A server push is a technique that makes it possible for a server to display information in a dynamic way. Server push takes advantage of a connection that is held open, so the server can send down more data any time it wants. The server sends data, but leaves the connection open. When the server wants to send more data, it does so, and the browser displays it, leaving the connection open, and so on until all the information has been displayed. It is a dynamic document mechanism.

The benefit of using server push is that the server has complete control over when and how often new data is sent down. The disadvantage is that the open connection is a drain on the server and may be wasteful. Client pull is an alternate dynamic document mechanism.

URLs:

An Exploration of Dynamic Documents in Netscape 1.1

This site explains server push & client pull in detail as well as displaying how these technique can be used.

PushMe Server-Push Framework

Mac users might be interested in looking at this shareware which enables Mac users to use server push.

National Debt Clock

This is an example of server push in which the national debt clock is continually updated, together with the average American family's share of the national debt.

W3E References:

client pull

CGI (Common Gateway Interface)

Detail:

If you use server push for an individual inlined image, the image will be replaced inside the document each time a new image is pushed. The document itself won't be changed as long as it isn't separately subject to server push. The roaring Netscape dragon was one of the earliest examples of this use of server push.