Hi all, not sure if this is the right forum in not please transfer me.

Ok my problem is I need to add some code, preferable HTML or XHTML I think to the HEAD TAG. Ive been running a site for sometime now and just realized that some people are still seeing the site from say Tuesday when I updated it on Thursday, how or what can I add so if the site has been stored in the users cache without being cleared after there visit it will automatically update it's self?

If this makes sense?