title: How does YouTube prevent the screensaver from showing up during video playback? (Windows)
body: <p>I have noticed that mi screensaver doesn't start while I'm watching videos on YouTube.
  I'm using Windows 7.</p>
  
  <p>This is the test:</p>
  
  <ol>
  <li>Set Windows screensaver to 1 minute.</li>
  <li>Browse to YouTube and play a video longer than 1 minute; ideally much longer.</li>
  <li>Note that your screensaver doesn't come up after the specified time (1 minute).</li>
  </ol>
  
  <p>I've tested using Firefox, Chrome and IE8. My Flash Player version is 10.3. (Youtube is using flash to play the videos). The same happens whether I watch the video in full-screen or not.</p>
  
  <p>Does anyone know how they do it? </p>
  
  <p>I've searched but all I found was people saying it's not possible, or tips for users to disable their screensaver while watching videos.</p>
  
  <hr>
  
  <p><strong>Please review all answers. Don't stick to the most voted.</strong></p>