function getWindowWidth() {
 return window.innerWidth ? window.innerWidth : document.body.offsetWidth;
}
function getWindowHeight() {
 return window.innerHeight ? window.innerHeight : document.body.offsetHeight;
}

var browerWidth = getWindowWidth();
var browerHeight = getWindowHeight();
if (browerWidth <= 1280 && browerHeight <= 800)
{
	document.getElementById("Layer4").style.visibility = 'hidden';
}
else
{
	document.getElementById("Layer4").style.visibility = '';
}