Unique Web Identification

From browser's point of view, what is the unique identification of web site? Nobody won't disagree that it's url in the address bar. Programmatically, you can simply get it by accessing document.location DOM object through Javascript in client side.

Thinking in-depth, it kind of plays a public key to specific page. Web page should be able to verify the signature by using that. The purpose is to prove that the page what the user is looking is exactly from the same server.

One interesting case is if you don’t want somebody else hosts your page inside IFrame in their page, you can write a simple javascript to prevent. Actually more interesting applications regarding web identification already utilize the technique.