var newWindow = null
function openWindow(name,windowname,properties) {
	if (!newWindow || newWindow.closed) {
	var x=screen.width ;
	var y=screen.height;
	var w=450;
	var h=590;
	var leftpos=eval(x-w)/2;
	var toppos=eval(y-h)/2;
		newWindow = window.open(name,windowname,'resizable=no,scrollbars=no,width='+ w + ',height=' + h + ',screenX=' + leftpos + ',screenY=' + toppos + ',top=' + toppos + ',left=' + leftpos,properties);
		// newWindow = window.open(name,windowname,'resizable=yes,scrollbars=yes,width=420,height=600');
		} 
	else {
	newWindow.close();
	var x=screen.width;
	var y=screen.height;
	var w=450;
	var h=590;
	var leftpos=eval(x-w)/2;
	var toppos=eval(y-h)/2;
		newWindow = window.open(name,windowname,'width='+ w + ',height=' + h + ',screenX=' + leftpos + ',screenY=' + toppos + ',top=' + toppos + ',left=' + leftpos,properties);

	
}
}