function abrirVentana(location, vwidth, vheight) {
	var vleft = screen.width/2 - vwidth/2;
	var vtop = screen.height/2 - vheight/2;
	window.open(location,'_blank','toolbar=no,location=no,status=no,directories=no,resizable=no,titlebar=no,width='+vwidth+',height='+vheight+',top='+vtop+',left='+vleft+',scrollbars=no');
}