title: How to parse JSON values and populate to combobox using EXTJS 4.2.1?
body: <p>The method:</p>
  <pre class="lang-js prettyprint-override"><code>Ext.Ajax.request({
      url: 'url',
      method: 'GET',
      timeout: 60000,
      params: {
          &quot;perviceTypeId&quot;: my.rec.data.prepeId
      },
      success: function(response) {
          var jsonResp = response.responseText;
          console.log(&quot;ajax data responseText::&quot; + jsonResp);
          //how to parse value and display and populate to deageType combobox
          var combo = Ext.getCmp('deageType');
      }
  });
  </code></pre>
  <p>The response is JSON:</p>
  <pre class="lang-js prettyprint-override"><code>{
    &quot;message&quot;: null,
    &quot;data&quot;: [
      {
        &quot;value&quot;: &quot;ESS&quot;,
        &quot;display&quot;: &quot;ESS&quot;
      },
      {
        &quot;value&quot;: &quot;ANS&quot;,
        &quot;display&quot;: &quot;ANS&quot;
      }
    ],
    &quot;errorCode&quot;: -1,
    &quot;totalCount&quot;: 1,
    &quot;messages&quot;: null,
    &quot;resultDate&quot;: 1615282701392,
    &quot;success&quot;: true
  }
  </code></pre>