title: Get size of file requested via ajax
body: <p>Here's what I'm hoping to do:</p>
  
  <p>I want to send an ajax request to a file (preferably with jQuery), and once the file has been loaded, determine the size of the requested file.</p>
  
  <p>After a bit of googling, it's clear that I don't even have a good idea of the right question to ask to figure this out.  Any help would be greatly appreciated.</p>