Filtering

<select id="multiselect" multiple="multiple">
    <option>Item1</option>
    <option>Item2</option>
</select>
<script>
$("#multiselect").kendoMultiSelect({
  filter: "startswith",
  filtering: function(e) {
      //get filter descriptor
      var filter = e.filter;

      // handle the event
  }
});
</script>

<select id="multiselect" multiple="multiple">
    <option>Item1</option>
    <option>Item2</option>
</select>
<script>
function multiselect_filtering(e) {
  //get filter descriptor
  var filter = e.filter;

  // handle the event
}
$("#multiselect").kendoMultiSelect({
  filter: "startswith"
});
var multiselect = $("#multiselect").data("kendoMultiSelect");
multiselect.bind("filtering", multiselect_filtering);
</script>

<select id="multiselect" multiple="multiple">
    <option>Item1</option>
    <option>Item2</option>
</select>
<script>
$("#multiselect").kendoMultiSelect({
  filter: "startswith",
  filtering: function(e) {
      var filter = e.filter;

      if (!filter.value) {
        //prevent filtering if the filter does not have value
        e.preventDefault();
      }
  }
});
</script>