I don't see what's so complicated here. PHP has TCP functions. The only requirement of your host is that you can disable their CGI Timeout: on a typical web server setup, scripts are killed after 90 seconds or so.
Keep in mind that your clients will need to make their port accessible. Some people (like me) have no choice about being behind a restrictive firewall.
A quick google search for PHP+TCP+connect found the fsockopen PHP command. There may be other ways to do this, but this one looks pretty straightforward. The example shows the other relevant commands:
http://www.phpbuilder.com/manual/function.fsockopen.php
If you let me know what it is exactly that you're trying to do, I may be able to help more.
Dampe: read the original post. The author requires that you're running his custom software - not a browser.
P.S. Regarding the "delay" approach, TCP itself will not kill your connection. A "checkpoint firewall" along the way might, however. The conventional keep-alive strategy is to send an occasional "NOOP" packet which the other party should ignore. This is certainly a valid and clean approach (and probably better than requiring an open port!)
Keep in mind that your clients will need to make their port accessible. Some people (like me) have no choice about being behind a restrictive firewall.
A quick google search for PHP+TCP+connect found the fsockopen PHP command. There may be other ways to do this, but this one looks pretty straightforward. The example shows the other relevant commands:
http://www.phpbuilder.com/manual/function.fsockopen.php
If you let me know what it is exactly that you're trying to do, I may be able to help more.
Dampe: read the original post. The author requires that you're running his custom software - not a browser.
P.S. Regarding the "delay" approach, TCP itself will not kill your connection. A "checkpoint firewall" along the way might, however. The conventional keep-alive strategy is to send an occasional "NOOP" packet which the other party should ignore. This is certainly a valid and clean approach (and probably better than requiring an open port!)