This approach seems to be fairly common today and is easy to do in perl. Lack of browser support is far less common today than it was in 1977...

What browser was around in 1977? {grin}

But as far as I can tell, the IE family has still not got any support for server push. So, server-push solutions work only when you know that the browser is non-standard in the same ways as Netscape browsers have been.

-- Randal L. Schwartz, Perl hacker