function abrir(pag) { 
	var px = (screen.availWidth-310)/2;
	var py = (screen.availHeight-20)/2 - 200;
	var prop = "toolbar=no,location=no,status=no,resizable=no,scrollbars=no,menubar=no,fullscreen=no,left=" + px + ",top=" + py + ",width=310,height=20";
	wind=window.open("","",prop);
	wind.focus()
	wind.location = pag;
	wind.name = "popup";
}