HTML and CSS Reference
In-Depth Information
and replacement URL, if specified. When the time expires, the browser
automatically retrieves the next URLyour new home page location.
13.2.4.1. A random URL generator
Another application for the combination of
Redirect
and
Refresh
HTTP
header fields is a perpetual, random URL generator. You'll need some
programming skills to create a server-side application that selects a ran-
dom URL from a prepared list and outputs a
Redirect
field that referen-
ces that URL along with a
Refresh
field that reinvokes the random-URL
application after some delay.
When the modern browser receives the complete header, it immediately
loads and displays the randomly selected document specified in the
Re-
direct
field's URL. After the delay specified in the
Refresh
field, the
browser reruns the random-URL generator on the server (as specified
in the refresh URL), and the cycle starts over. The result is an endless
cycle of random URLs displayed at regular intervals.
13.2.5. Performance Considerations
Client-pull documents consume extra network resources, especially
when the refresh delay is small, because each refresh may involve a
new connection to a server. It may take a browser several seconds to
contact the server and begin retrieving the document. As a result, rapid
updates generally are not feasible, especially over slow network connec-
tions.
Use client-pull dynamic documents for low-frequency updates of entire
documents, or for cycling among documents without user intervention.
