function canUseJScript() {
   if (navigator.userAgent.indexOf("Mozilla/") == 0) {
      return (parseInt(navigator.appVersion) >= 4);
   }
   return false;	
}

function hashLoginPassword(form) {
  if (canUseJScript()) {
    form.hashedTwicePassword.value = MD5(MD5(form.password.value) + form.challenge.value);
//    form.password.value = "";
    form.hashed.value = true;
    form.onsubmit = null;
  }
  return true;
}