登记页面对应的函数得不到文本控件的值

<br />$.post('{:U("Register/register")}', $('#register'), function(str) {     //  .serialize()<br />

<br />//注册<br />    public function register() { <br />        $data['u_username'] = strtolower(I('name', '', 'trim'));<br />        $data['u_phone'] = I('phone', '', 'trim');<br />        $data['u_email'] = I('email', '', 'trim');<br />        $data['u_password'] = I('pass');<br />        $data['repassword'] = I('rpass');<br />        $rpass = I('rpass');<br />        ... ...<br />

<br />if (email === 0 || phone === 0 || code === 0 || username === 0 || password === 0 || rpassword === 0) {<br />...<br />

<br />if (document.getElementById("email").value === 0 || document.getElementById("phone").value === 0 || document.getElementById("code").value === 0 || document.getElementById("username").value === 0 || document.getElementById("password").value === 0 || document.getElementById("rpassword").value === 0) {<br />

<br /><input  name="email" id="email" maxlength="30" /><br />