title: Getting bad request (#400) on Ajax calls using Yii 2
body: <p>This is my code:</p>
  
  <pre><code>$(document).on('change', '#tblhotel-int_zone_id', function(e){
      var zoneId = $(this).val();
      var form_data = {
          zone: zoneId
      };
      $.ajax({
          url: "state",
          type: "POST",
          data: form_data,
          success: function(response)
          {
              alert(response);
          }
      });
  });
  </code></pre>
  
  <p>This shows:</p>
  
  <blockquote>
    <p>Bad Request (#400): Unable to verify your data submission.</p>
  </blockquote>
  
  <p>And I already have <code>&lt;?= Html::csrfMetaTags() ?&gt;</code>. How can I fix this problem?</p>