title: Programmatically determine DPI via the browser?
body: <p>I would like to programmaticaly determine the DPI of a user's display in order to show a web page at a precise number of units (centimeters/inches). I know it a weird request: it's for a visualization research project and it's kind of a control. We currently do it by having the user place a credit card to the screen and match a resizable div (via Mootools) to the real credit card, and voila we can get the DPI and display the page correctly.</p>
  
  <p>Can anyone think of a programmatic way to do this?</p>