title: How do I lock the orientation to portrait mode in a Mobile Web Application?
body: <p>I am making a web application using html, and javascript for mobile devices (phones). How can I lock the screen orientation in portrait? Are there any extensions, or frameworks to do this?</p>
  
  <p>EDIT: 
  When the user goes into landscape mode, I want a only a div (in the shape of a box if it matters) to be displayed that contains the text "please turn your device to portrait."</p>