title: Error in accessing post json data in yii2
body: <p>Am passing data to yii2 using ajax request but i keep on getting a 500 error</p>
  
  <p>This is the ajax request code:</p>
  
  <pre><code>&lt;?php 
   $script = &lt;&lt;&lt; JS
  
       $('form#forward_pr').on('beforeSubmit', function(e){
      var keys = $('#grid').yiiGridView('getSelectedRows');
       $.post({
         url: "forwardpr", // your controller action
         dataType: 'json',
         data: {keylist: keys},
         success: function(data) {
            alert('I did it! Processed checked rows.')
         },
       error: function(err){
         console.log("server error");
         }
      });
         return false;
      }  ) ;
  
      JS;
      $this-&gt;registerJS($script);
   ?&gt;
  </code></pre>
  
  <p>When i do console.log(keys) this returns</p>
  
  <pre><code>[0, 1]
  </code></pre>
  
  <p>This is my controller code:</p>
  
  <pre><code>if (Yii::$app-&gt;request-&gt;post()) {
           echo $post = json_encode($_POST['keys']);
            if (isset($_POST['keylist'])) {
                  $keys = \yii\helpers\Json::decode($_POST['keylist']);
                print_r($keys);
              }else{
                echo "1";
            }
  </code></pre>
  
  <p>The above always executes the error part of post request, What could be wrong;</p>