var WS;
var HS;
var popup;

window.onload=function(){
   WS = document.body.clientWidth;
   HS = document.body.clientHeight;
}

function openWindow(href){
	var w = WS, h = HS;
	if (document.all) {
	}
	else if (document.layers) {
	   w = window.innerWidth;
	   h = window.innerHeight;
	}
	var popW = 480, popH = 480;
	var leftPos = (w-popW)/2;
	var topPos = (h-popH)/2;
  	popup = window.open(href,'2ehandkeukenapparatuur','width=480,height=480,scrollbars=no,toolbar=no,location=no,left='+leftPos+',top='+topPos);
	return false;
}