title: Lock the screen with a popup till the time page gets loaded completely
body: <p>My page takes quite sometime to load a variety of controls and menu images. I want to show a popup window with progress bar on it. The user must not be able to access the original page on the web-browser when this popup is showing. </p>
  
  <p>When the page has loaded completely, this popup must disappear. How to do this?</p>