Form.Request冻结

Question

当我使用以下代码时，Form.Request将不会发送任何内容而是冻结。这有什么问题？ （对不好的缩进，代码由SecureSocial（http://securesocial.ws）生成）

<script type="text/javascript">
window.addEvent('domready', function(e) {
    var anchor = document.id('form_anchor');
    new Form.Request(anchor.getElement('form'), anchor);
});
</script>
<div id="form_anchor">
    <div class="page-header">
        <h1>Login</h1>
    </div>
            <div class="clearfix">
                <p>Use your existing account on one of the following networks to log in.</p>
                <p>
                    <a href="/authenticate/twitter"> <img src="/assets/securesocial/images/providers/twitter.png"/></a>
                    <a href="/authenticate/facebook"> <img src="/assets/securesocial/images/providers/facebook.png"/></a>
                </p>
            </div>
            <div class="clearfix">
                    <p>Or login using a username and password.</p>
                <form action = "http://localhost:9000/authenticate/userpass"
                      class="form-horizontal" autocomplete="off" method="POST">
                    <fieldset>
<div class="control-group  " id="username_field">
    <label class="control-label" for="username">Email</label>
    <div class="controls">
    <input type="text" id="username" name="username" value="" class="input-xlarge">

            <span class="help-block"></span>
    </div>
</div>
<div class="control-group  " id="password_field">
    <label class="control-label" for="password">Password</label>
    <div class="controls">
    <input type="password" id="password" name="password" value="" class="input-xlarge">

            <span class="help-block"></span>
    </div>
</div>
                        <div class="form-actions" style="background-color:transparent;border:0">
                            <button type="submit" class="btn btn-large btn-primary">Login</button>
                        </div>
                        <div class="clearfix">
                            <a href="/reset"><p>Did you forget your password? </a></p>
                        </div>
                            <div class="clearfix">
                                <p>If you dont have an account with us yet you can sign up <a href="/signup">here</a></p>
                            </div>
                    </fieldset>
                </form>
            </div>
</div>