redirecting a webpage from site A to site B without changing url

I would like to redirect the user when he/she clicks on a li开发者_高级运维nk () to b.com when the user is in a.com without displaying the change in the browser's address bar.

How would I do this? Please help.

Thanks.

You'd either have your web server proxy the other site, using something like mod_proxy, or some some squid setup. Or, you have a page with a single iframe on it that displays the other site.