title: Detect iFrame embedding in Javascript
body: <p>I have an application that has a certain page -- let's call it Page A. Page A is sometimes a top-level page, but also sometimes is embedded as an iframe within page B. All pages come from the same server and there are no cross-domain issues.</p>
  
  <p>I have a greasemonkey script that runs on page A. How can the greasemonkey script detect whether page A is within the iframe context or not?</p>