问自动完成功能未定义

EN

<link href="~/Content/themes/base/jquery-ui.css" rel="stylesheet" />
<script src="~/Scripts/jquery-2.1.1.js"></script>
<script src="~/Scripts/jquery-ui-1.10.4.js"></script> 
 $("#discUsers")
      // don't navigate away from the field on tab when selecting an item
      .bind("keydown", function (event) {
          if (event.keyCode === $.ui.keyCode.TAB &&
              $(this).autocomplete("instance").menu.active) {
              event.preventDefault();
          }
      })
      **.autocomplete**  ({
          minLength: 0,
          source: function (request, response) {
              // delegate back to autocomplete, but extract the last term
              response($.ui.autocomplete.filter(
                availableTags, extractLast(request.term)));
          },
          focus: function () {
              // prevent value inserted on focus
              return false;
          },
          select: function (event, ui) {
              var terms = split(this.value);
              // remove the current input
              terms.pop();
              // add the selected item
              terms.push(ui.item.value);
              // add placeholder to get the comma-and-space at the end
              terms.push("");
              this.value = terms.join(", ");
              return false;
          }
      });
});