form.submit()不能提交表单的原因分析

<div id="register">
<h4>会员注册</h4>
<div class="formdiv">
<form method="post" action="register.php?action=register" name="register" id="registerForm">
<dl>
<dt>请认真填写以下内容</dt>
<dd class="hasspan">
用户名：<input type="text" name="username">
</dd>
<dd class="hasspan">
密码：<input type="password" name="pwd">
</dd>
<dd class="hasspan">
确认密码：<input type="password" name="pwdagain">
</dd>
<dd id="tximg">
<img src="img/face/m01.gif" alt="选择头像" id="faceimg">
<input type="hidden" name="touxiang" value="">
<label id="imgsrclabel">m01.gif</label>
</dd>
<dd style="margin-right:120px;">
验证码：<input type="text" name="code">
<span>
<img src="code.php" alt="code" id="code" name="code">
<a href="#code" id="change">换一张</a>
</span>
</dd>
<dd class="btns">
<input type="button" name="submit" id="submit" value="注册">
<input type="button" name="quit" id="quit" value="退出">
</dd>
</dl>
</form>
</div>
</div>

/*注册表单提交*/
function formDeal()
{
var btnSubmit = document.getElementById('submit');
var formId = document.getElementById('registerForm');
btnSubmit.onclick = function()
{
//表单的submit()方法不能提交表单
formId.submit();
}

}

if(!empty($_GET['action']) && $_GET['action'] == 'register')
{
echo '你提交了数据';
exit();
}

this.type="submit"