<form id="myForm">
  <input type="text" name="name" value="John">
  <input type="email" name="email" value="john@example.com">
  <input type="number" name="age" value="25">
</form>

$(document).ready(function() {
  $("#myForm").submit(function(event) {
    event.preventDefault(); // 阻止表单默认提交行为
    var formData = $(this).serializeArray();
    var jsonData = {};
    $.each(formData, function(index, field) {
      jsonData[field.name] = field.value;
    });
    console.log(jsonData);
  });
});

{
  "name": "John",
  "email": "john@example.com",
  "age": "25"
}

<form id="myForm">
  <input type="text" name="name" value="John">
  <input type="checkbox" name="hobbies" value="reading" checked>阅读
  <input type="checkbox" name="hobbies" value="sports" checked>运动
  <input type="radio" name="gender" value="male" checked>男
  <input type="radio" name="gender" value="female">女
  <select name="city">
    <option value="beijing">北京</option>
    <option value="shanghai">上海</option>
    <option value="guangzhou" selected>广州</option>
  </select>
</form>

$(document).ready(function() {
  $("#myForm").submit(function(event) {
    event.preventDefault(); // 阻止表单默认提交行为
    var formData = $(this).serializeArray();
    var jsonData = {};
    $.each(formData, function(index, field) {
      // 对于同一个名称的表单元素（例如复选框），会被序列化为相同名称的属性值数组
      if (jsonData[field.name] !== undefined) {
        if (!jsonData[field.name].push) {
          jsonData[field.name] = [jsonData[field.name]];
        }
        jsonData[field.name].push(field.value || '');
      } else { // 普通表单元素
        jsonData[field.name] = field.value || '';
      }
    });
    console.log(jsonData);
  });
});

{
  "name": "John",
  "hobbies": [
    "reading",
    "sports"
  ],
  "gender": "male",
  "city": "guangzhou"
}