function openWindow (url,width,height) {
	urlstring=url;
	
	LeftPosition = (screen.width) ? (screen.width-width)/2 : 0;
	TopPosition = (screen.height) ? (screen.height-height)/2 : 0;
	
	window1=window.open(urlstring,'window1','top=' + TopPosition + ',left=' + LeftPosition + 'directories=no,hotkeys=no,location=no,menubar=no,status=no,toolbar=no,resizable=yes,scrollbars=yes,height=' + height +',width='+ width)
	window1.focus();
	
	if (window1 != null && window1.opener == null)
		window1.opener=window;
}