title: IE9 devicePixelRatio equivalent
body: <p>Has anyone discovered a reliable method to determine the device pixel ratio for Windows Phone 7.5 (Mango).</p>
  
  <p>It is based off of IE9. In Webkit based browsers we have window.devicePixelRatio or using window.matchMedia() with the appropriate media query.</p>
  
  <p>In Windows Mobile I can determine pixel ratio by doing:
  screen.deviceXDPI / screen.logicalXDPI
  though this appears to only be reliable once the page has been fully rendered. Prior to that deviceXDPI reports the same as logicalXDPI</p>
  
  <p>Has anyone found a solution?</p>
  
  <p>Thanks for any help/suggestions</p>