var winLeft,winTop;
function calculate_center(winWidth,winHeight)
{
   	xCenter=screen.width/2;
	yCenter=screen.height/2;
	winLeft=xCenter-winWidth/2;
	winTop=yCenter-winHeight/2;
}
function popupScriptToOpensurvey(windowqs)
{
	calculate_center(500,370);
	window.open(windowqs, 'CustomPopUp', "top="+winTop+",left="+winLeft+",width=500,height=370,menubar=no,scrollbars=0,resizable=no,toolbar=no,status=no,directories=no,titlebar=no");
}