addLoadListener(init);

function init()
{
  window.onresize = function()
  {
  	var nContHt = 0;
  	
  	nContHt = document.getElementById('contdisp').offsetHeight;
       
    var size = getViewportSize();
    
    
    // make adjustments to the sizing for min/max numbers
    if ( size[1] < nContHt ) 
    	{
    	size[1] = nContHt;
    	}
      
    if ( size[1] > nContHt )
    	{
    	nTopOffset = (size[1] - nContHt) / 2;
    	document.getElementById('contdisp').style.margin = nTopOffset + "px 0 0 0";
		}
  };

  window.onresize();


  return true;
}

function getViewportSize()
{
  var size = [0, 0];

  if (typeof window.innerWidth != 'undefined')
  {
    size = [
        window.innerWidth,
        window.innerHeight
    ];
  }
  else if (typeof document.documentElement != 'undefined'
      && typeof document.documentElement.clientWidth != 'undefined'
      && document.documentElement.clientWidth != 0)
  {
    size = [
        document.documentElement.clientWidth,
        document.documentElement.clientHeight
    ];
  }
  else
  {
    size = [
        document.getElementsByTagName('body')[0].clientWidth,
        document.getElementsByTagName('body')[0].clientHeight
    ];
  }

  return size;
}


function addLoadListener(fn)
{
  if (typeof window.addEventListener != 'undefined')
  {
    window.addEventListener('load', fn, false);
  }
  else if (typeof document.addEventListener != 'undefined')
  {
    document.addEventListener('load', fn, false);
  }
  else if (typeof window.attachEvent != 'undefined')
  {
    window.attachEvent('onload', fn);
  }
  else
  {
    var oldfn = window.onload;
    if (typeof window.onload != 'function')
    {
      window.onload = fn;
    }
    else
    {
      window.onload = function()
      {
        oldfn();
        fn();
      };
    }
  }
}