JavaScript Validator ( JSV )的使用方法？

想要找可以在註冊時，即時讓使用者知道這個帳號可不可用的模組。

結果找到兩個：

Username originality AJAX check：
還在dev狀態，且最後更新是2007-Jul-24，因為我有用CAPTCHA，不知為何，安裝完後可以順利使用，但「check」的按鈕不會出現在username的input旁邊。(雖然應該可以手動改啦！不過因為是dev，所以怕怕的)

JavaScript Validator ( JSV )：
這個感覺比較好，可以做到像這樣

不過看他的說明，我還是不太懂耶！這些原始碼是要寫到哪裡，我才有辦法讓使用者在註冊表單用到這些東西呢？

<?php
/**
* Implementation of hook_menu().
*/
function ssp_menu($may_cache){
$items = array();

$items[] = array(
'path' => 'validate/user/'.arg(2),
'title' => t(''),
'callback' => 'ssp_validate_user',
'callback arguments' => array(arg(2)),
'access' => TRUE,
);

return $items;
}

/**
* Implementation of hook_form_alter();
*/
function ssp_form_alter($form_id, &$form){
if ($form_id == 'user_login' || $form_id == 'user_login_block'){
// We want the username to have a validation type of request
$form['name']['#attributes']['class'] = 'request';
// and we want the path to be /validate/user (an additional argument of the value is passed)
$form['name']['#attributes']['validator-path'] = '/validate/user';
}
}

function ssp_validate_user($username){
$output = array();
$username = check_plain($username);

if ($user = user_load(array('name' => $username))){
// user is found
$output['valid'] = TRUE;
}
else {
// user is not found, provide an error message.
$output['valid'] = FALSE;
$output['message'] = t('Sorry the user !username was not found.', array('!username' => $username));
}

// format the $output array as a javascript readable object which is then displayed, and
// then we exit; to display only this JSON string on the page being requested by the javascript.
echo json_encode($output);
exit;
}
?>