<div id="filter"></div>
<script>
  var data = [
      { name: "Jane Doe", birthDate: new Date(1990, 0, 15) },
      { name: "John Doe", birthDate: new Date(1985, 5, 20) }
    ];

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

  $("#filter").kendoFilter({
    dataSource: dataSource,
    operators: {
        date: {
            custom: {
                text: "Custom Date Filter",
                handler: function(data) {
                    console.log("Custom date filter applied", data);
                    return true;
                }
            }
        }
    },
    fields: [
      { name: "birthDate", type: "date", label: "Birth Date" }
    ]
  });
</script>