function isEmailAddress(theElement, nombre_del_elemento )
{
var s = theElement.value;
var filter=/^[A-Za-z][A-Za-z0-9_.]*@[A-Za-z0-9_]+\.[A-Za-z0-9_.]+[A-za-z]$/;
if (s.length == 0 ); 
   if (filter.test(s))
      return true;
   else
     alert("Ingresa una dirección de correo valida, gracias.");
theElement.focus();
return false;
}

function popup(URL) {
day = new Date();
id = day.getTime();
eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=300,height=380,left=25,top=0');");
}