<div id="filter"></div>
<script>
  var data = [
      { name: "Jane Doe", age: 30 },
      { name: "John Doe", age: 33 }
    ];

  var dataSource = new kendo.data.DataSource({
    data: data
  });

  $("#filter").kendoFilter({
    dataSource: dataSource,
    operators: {
        number: {
            isnull: "Is null value"
        }
    },
    fields: [
      { name: "age", type: "number", label: "Age" }
    ]
  });
</script>