You can use JavaScript. Google 'javascript cookies' and 'javascript redirect' to see good examples. The problem with this is that the client could have javascript turned off, in that case you could have the webpage detect that and display a message telling the client to turn it on.

The other way is to have the page be a perl script, i.e. if it is the index page, remove index.htm or index.html and use index.cgi or index.pl. You will need to have those index pages set up in apache's cfg (or what ever webserver you are using) to be displayed as an index page. Lots of info on this if you search around.

I hope that this helps, and good luck,

Cameron