发送数据会给出[object HTMLInputElement]作为查询响应

我正在尝试向合作伙伴端点发送用户表单数据，如下所示：

$('#registrationFrm').on('submit', function(e){
e.preventDefault();
$.ajax({
type: "POST",
url: "https://pixel.plexop.com/?country="+countryid+"&_v=6&name="+firstName+"&lastname="+lastName+"&phone="+phone
+"&email="+emailid+"&ud=&e=2&adv=1&a=4&f=221161&FormId=1807&SerialId=1210053",
data: $("#registrationFrm").serialize(),
success: function() {
alert('success');
 }
});
});

<form id="registrationFrm" >
      <div class="form-group has-feedback">
        <input type="text" class="form-control" placeholder="First Name" name="firstName" id="firstName" required />
        <span class="glyphicon glyphicon-user form-control-feedback"></span>
      </div>
      <div class="form-group has-feedback">
        <input type="text" class="form-control" placeholder="Last Name" name="lastName" id="lastName" required />
        <span class="glyphicon glyphicon-user form-control-feedback"></span>
      </div>
      <div class="form-group has-feedback">
        <input type="tel" class="form-control" placeholder="Phone No" name="phone" id="phone" required />
        <span class="glyphicon glyphicon-earphone form-control-feedback"></span>

我返回200 OK，但从数据开始，当我在网络上检查它时，我会发送此信息：

Query string: country   "[object HTMLSelectElement]
Query string: name  "[object HTMLInputElement]
Query string: lastname  "[object HTMLInputElement]"

我的表单如下所示：

$('#registrationFrm').on('submit', function(e){
e.preventDefault();
$.ajax({
type: "POST",
url: "https://pixel.plexop.com/?country="+countryid+"&_v=6&name="+firstName+"&lastname="+lastName+"&phone="+phone
+"&email="+emailid+"&ud=&e=2&adv=1&a=4&f=221161&FormId=1807&SerialId=1210053",
data: $("#registrationFrm").serialize(),
success: function() {
alert('success');
 }
});
});

<form id="registrationFrm" >
      <div class="form-group has-feedback">
        <input type="text" class="form-control" placeholder="First Name" name="firstName" id="firstName" required />
        <span class="glyphicon glyphicon-user form-control-feedback"></span>
      </div>
      <div class="form-group has-feedback">
        <input type="text" class="form-control" placeholder="Last Name" name="lastName" id="lastName" required />
        <span class="glyphicon glyphicon-user form-control-feedback"></span>
      </div>
      <div class="form-group has-feedback">
        <input type="tel" class="form-control" placeholder="Phone No" name="phone" id="phone" required />
        <span class="glyphicon glyphicon-earphone form-control-feedback"></span>

---

我在这里做错了什么？

可能，您将变量定义为：

const firstName = document.getElementById('firstName');
/*and so*/

但你应该这样做：

const firstName = document.getElementById('firstName').value;

UPD：

---

你能发布一个完整的代码示例吗？查看countryid、firstName、lastName、phone和emailid的所有var声明，以及表单字段的相关HTML都会有所帮助。因此，您正在URL和请求正文中发送数据？我根本没有向其中添加任何常量。这应该在index.html中实现吗？您最好这样做，但您可以这样做：再次检查我的答案