Port Testing via www page

I apologize in advance if this is not the correct forum for this.
Please direct me to the appropriate posting group if this is not the
best place.
Does anyone have any ideas on where I can find code examples on testing
for open tcp ports using a www page?
The applications I work with require various ports to be open.
Obviously if the port isn't open, the application doesn't work.
Unfortunately the errors generated by the applications are not always
clear that the problem is port related. I was hoping to create a port
tester to verify if the required ports are open. I would prefer this
route over a stand alone program as many of the end users are in
financial centers and they aren't to keen on 3rd party port scanning
software probing their network.
I know there are sites already in existence that do this (shields up,
etc), but I was hoping for something less elaborate and to customize it
for just the ports needed for my applications. I thank you for
reviewing this post.