function open_window (url, name, height, width, scrollbars, resize) {
	var screenX=((screen.width - width)/2);
	var left=screenX;
	var screenY=((screen.height - height)/2);
	var top=screenY;
	if (screenX<0) { screenX = 0; }
	if (screenY<0) { screenY = 0; }
	if (left<0) { left = 0; }
	if (top<0) { top = 0; }
	window_properties = "resizable=" + resize + ",toolbar=no,scrollbars=" + scrollbars + ",status=no,menu=no,width=" + width + ",height=" + height + ",left=" + left + ",top=" + top + ",screenX=" + screenX + ",screenY=" + screenY;
	window.open(url,name,window_properties);
}