title: Working with canvas in different screen sizes
body: <p>I'm planing to create a simple game using the HTML5 <code>&lt;canvas&gt;</code> tag and compile the code into a native application using Phonegap, but the problem is that <code>canvas</code> use coordinates that are not relative to the size of it, so <code>20,20</code> on a 960x640 screen is different on a 480x800 one.</p>
  
  <p>So I want to know how to work with a <code>&lt;canvas&gt;</code> (which will be in fullscreen) on different screen sizes.</p>