title: IFrame buster files - what's their purpose?
body: <p>Looking at a few advertising companies (DoubleClick, Atlas), I've come across the concept of iframe buster files, that are hosted on the same host as the ad publisher (one example: <a href="http://www.adopstools.com/ibusters/atlas/atlas_rm.htm" rel="noreferrer">http://www.adopstools.com/ibusters/atlas/atlas_rm.htm</a>, and there's a lot of JS code that works with that page).</p>
  
  <p>I read that they're used to dynamically resize the iframe. Is that all there is to iframe busters? Does hosting them on publisher's host help with JS cross-domain restrictions?</p>
  
  <p><strong>Added</strong>: I'm referring to the use case described here: <a href="http://blog.operative.com/?tag=iframe" rel="noreferrer">http://blog.operative.com/?tag=iframe</a>, and not just changing the iframe source document to the top level.</p>