function openwindow(pageis, heightis, widthis)
{
 	var yposition=(screen.availHeight-heightis)/2;
 	var xposition=(screen.availWidth-widthis)/2;
 	
	newindow=window.open(pageis,"NewWindow","status=no,location=no,toolbar=no,scrollbars=no,directories=no,resizable=yes,width="+widthis+",height="+heightis+",top="+yposition+",left="+xposition);

	return false;
}