jQuery验证和AJAX提交表单如何编写e.preventDefault()

<script src="https://cdn.jsdelivr.net/npm/jquery"></script>
<script src="https://cdn.jsdelivr.net/npm/jquery-validation"></script>

<form id="myForm">
  <label for="username">用户名:</label>
  <input type="text" id="username" name="username" required>
  <br>
  <label for="password">密码:</label>
  <input type="password" id="password" name="password" required>
  <br>
  <input type="submit" value="提交">
</form>

<script>
  $(document).ready(function() {
    $('#myForm').validate({
      rules: {
        username: {
          required: true
        },
        password: {
          required: true
        }
      },
      messages: {
        username: {
          required: "请输入用户名"
        },
        password: {
          required: "请输入密码"
        }
      },
      submitHandler: function(form) {
        // 在这里可以进行AJAX提交表单的操作
        e.preventDefault(); // 阻止表单的默认提交行为
      }
    });
  });
</script>