ISA server through hardware firewall

Does anybody know the ports to be opened on a Hardware firewall and a ISA server to enable web browsing?

Me HW firewall is configured to use port 80 buth the proxy of me ISP is using 8080.
The ISA firewall is default using port 8080.

I’ve enabled the port 8080 on my HW firewall and all seems to work… BUTH

I can’t browse sites with javascripts.
* example: http://www.eureco.be *
* go to @home *

If anybody know my configuration error please let me know.

Thanks