way to listen to port 127.0.0.1

[rgould8 at aol.com]

I have a need to write a little "listener app" that lurks in the 
background, waiting for the user to do something on a webpage in a 
browser, like Safari.  When a javascript routine on the web-page gets 
called, I need my Rev app to receive a few strings of text from the 
browser.

The only way I can think to do that is to somehow pass data through 
port 127.0.0.1 and have Rev waiting patiently to receive that data.  
I'm just not sure how to go about sniffing for data from that port.  
Has anyone done that type of thing before that could share some code.

Note that this is for a kiosk environment where I have full control 
over the hardware and software.  This is for a Mac.