function openWindow(url, name, w, h)  //opens a new 'centered' window of selectable dimensions	
{
var winl = (screen.width - w ) / 2;
var wint = (screen.height - h) / 2;
	winprops = 'height='+h+',width='+w+',top='+wint+',left='+winl+''
	popupWin = window.open(url, name, winprops);
};