var timeoutforcenter
function setToAlwaysCenter(elem)
{
var iebody=(document.compatMode && document.compatMode != "BackCompat")? document.documentElement : document.body

var browserh = document.all?iebody.clientHeight : innerHeight
var browserw = document.all?iebody.clientWidth : innerWidth

var dsocleft = document.all? iebody.scrollLeft : pageXOffset
var dsoctop  = document.all? iebody.scrollTop : pageYOffset

var left = (browserw == 0) ? 50 : parseInt((browserw - elem.offsetWidth) / 2 + dsocleft, 10);
var top = (browserh == 0) ? 50 : parseInt((browserh - elem.offsetHeight) / 2 + dsoctop , 10);

elem.style.left = left + 'px';
elem.style.top = top + 'px';

timeoutforcenter = setTimeout( function () { setToAlwaysCenter(elem); }, 100);
}

function stopAlwaysCenter()
{
  clearTimeout(timeoutforcenter);
}


function gameBegin()
{ 
  ShowgameBox();
}
function ShowgameBox(){
	document.getElementById("black_overlay").style.display="block";
	document.getElementById("cropbox").style.display="block";
	setToAlwaysCenter(document.getElementById('cropbox'));
}
function HidegameBox(){
	document.getElementById("black_overlay").style.display="none";
	document.getElementById("cropbox").style.display="none";
	stopAlwaysCenter();
}// JavaScript Document