function centerDesign(div){ 
  var winHeight = window.innerHeight ? window.innerHeight : window.documentElement ? window.documentElement.offsetHeight : document.body.offsetHeight;
  var divHeight = document.getElementById(div).offsetHeight;
  var intDifHeight = winHeight - divHeight;
  
  if(divHeight<winHeight) {
  	document.getElementById('spacer').style.height = intDifHeight/2 + "px";
  }
  else {
    document.getElementById('spacer').style.height = 0 + "px"; 
  }
  document.getElementById(div).style.visibility = "visible";
}