title: How to make popup stay in the center of the screen.
body: <p>What I need to do to make popup appear in the center of the screen in the following scenarios.</p>
  
  <p>1- Scrolling the window
  2- Resizing the window
  3- Window is resized that it equals the size of mobile phone screen.</p>
  
  <p>Demo '<a href="http://jsfiddle.net/mdsa/rDT7Y/" rel="nofollow">http://jsfiddle.net/mdsa/rDT7Y/</a>'<code></code></p>