How does this work? I was under the impression that when I clicked a link in a webpage it just opened that link as if I'd typed it into my URL bar. How does jwz know were I'm clicking from?
> The HTTP referer (a misspelling of referrer) is an optional HTTP header field that identifies the address of the webpage (i.e., the URI or IRI), which is linked to the resource being requested. By checking the referrer, the new webpage can see where the request originated.
> The Referer header field allows servers to generate back-links to other resources for simple analytics, logging, optimized caching, etc. It also allows obsolete or mistyped links to be found for maintenance. Some servers use the Referer header field as a means of denying links from other sites (so-called "deep linking") or restricting cross-site request forgery (CSRF), but not all requests contain it.
