popup.js

document.addEventListener('DOMContentLoaded', function() {
    document.getElementById("myTable").onclick = function(e){
        //var item = $(this);
        //var headerItem = item.data('header');
        console.log(e);
    };

    document.onkeyup = function() {
      var input, filter, table, tr, td, i, txtValue;
      input = document.getElementById("myInput");
      filter = input.value.toUpperCase();
      table = document.getElementById("myTable");
      tr = table.getElementsByTagName("tr");

      for (i = 0; i < tr.length; i++) {
        td = tr[i].getElementsByTagName("td")[0];
        if (td) {
          txtValue = td.textContent || td.innerText;
          if (txtValue.toUpperCase().indexOf(filter) > -1) {
            tr[i].style.display = "";
          } else {
            tr[i].style.display = "none";
          }
        }
      }
    };

}, false);