function popup( url, name, width, height )
	{
	var x = Math.floor((screen.availWidth - width)/2);
	var y = Math.floor((screen.availHeight - height)/2);
	
		if( window.windows == null ) window.windows = {};
//		if( window.windows[name] != null && !window.windows[name].closed ) window.windows[name].close();
	
	window.windows[name] = window.open(url, name, 'scrollbars=no,resizable=yes,width=' + width + ',height=' + height + ',left=' + x + ',top=' + y);
	window.windows[name].focus();
	
	return false;
	}