@pyroDec 18.2003 — #The best way would be to use CSS, probably. Give a <div> and ID, and insert your message into it. Then, use the [URL=http://www.w3.org/TR/REC-CSS2/cascade.html#at-import]@imput[/URL] rule to include a bit of CSS that will hide the div (display: none?. Old browser will not read the imported stylesheets, but newer one's will (thus hiding the message).
@AdamGundryDec 20.2003 — #On the server-side, you could use PHP's get_browser() function to determine whether your browser is capable of handling the content: