If you are trying to figure out where a form posts (for instance to see whether or not it submits information securely) and the post location isn’t readily view-able in the page source, here is how to do it:
Using Firefox, (download if necessary) open Firebug.
Hit Ctrl+Shift+C to open the console.
Switch to the Net tab and submit the form. (The console window needs to be open before you hit submit.)
In the list window you should see a POST request with the endpoint and the complete information about the request including Headers, Post, Response, JSON, Cache, and Cookies.
You can copy the endpoint location by right clicking and selecting Copy Location.