function popUp(arch, id, ancho, altura)
{
	var t = (768 - 108 - altura) / 2;
	var l = (1024 - ancho) / 2;
	window.open(arch, id, 'toolbar=0,scrollbars=0,location=no,statusbar=0,menubar=0,resizable=0,width=' + ancho + ',height=' + altura + ',left=' + l + ',top=' + t + "')");
}