jQuery get viewport size

viewport.js

  // -----------
  // Debugger that shows view port size. Helps when making responsive designs.
  // -----------
  function showViewPortSize(display) {
    if(display) {
      var height = window.innerHeight;
      var width = window.innerWidth;
      jQuery('body').prepend('<div id="viewportsize" style="z-index:9999;position:fixed;bottom:0px;left:0px;color:#fff;background:#000;padding:10px">Height: '+height+'<br>Width: '+width+'</div>');
      jQuery(window).resize(function() {
              height = window.innerHeight;
              width = window.innerWidth;
              jQuery('#viewportsize').html('Height: '+height+'<br>Width: '+width);
      });
    }
  }

  $(document).ready(function(){
     showViewPortSize(true);
  });

Version based on the comment of @xmoonlight from this gist https://gist.github.com/bohman/1351439