     <span class="lang-field lang-en">Latency</span>  
            <span class="lang-field lang-cn">延迟</span>
          </th>
          <th width="70">
            <div class="btn-group" role="group" dir="ltr">
              <button class="btn btn-outline-secondary btn-sm" onclick="downloadAsCSV()"><img height="20px" src="assets/icon-csv.png" /></button>
              <button class="btn btn-outline-secondary btn-sm" onclick="downloadAsJSON()"><img height="20px" src="assets/icon-json.png" /></button>
   