Assuming http://example.com/js/script.js fires an AJAX request against some relative URL, how do I get the absolute URL that ended up being requested?
For example, if I request image.png from http://example.com/js/script.js I'd expect to get back http://example.com/js/image.png. If, however, I requested /image.png from the same URL I'd expect to get back http://example.com/image.png.
This question is tricky for two reasons:
I don't believe it's possible to get a script's URL from inside it.UPDATE: I incorrectly assumed that AJAX requests are issued relative to the script location. It turns out that they are issued relative tolocation.href. This simplifies the situation.- I don't believe that 
XMLHttpRequestexposes the request URL, not to mention its absolute form. 
Any ideas?