I'm trying to filter a grid on a single column using input from a separate text field.  Please see the code shown below.  The function fires, the filter "x" is set as expected but the grid is not filtered.

<div id="wb_sbSourceCharacteristicValues" style="position:absolute;left:30px;top:89px;width:400px;height:48px;z-index:4;">
<script>function lstSourceCharacteristicValuesSearch() {
var x = document.getElementById("sbSourceCharacteristicValues").value;
$(".lstSourceCharacteristicValues_table").igGridFiltering("destroy");
$(".lstSourceCharacteristicValues_table").igGridFiltering("filter", ([{fieldName: "lookup_display", expr: x, cond: "contains"}]));
}</script><div id="sbSourceCharacteristicValueslstSourceCharacteristicValues" style="position:abosolute; left:50px; top:625px; width:400px; height:48px; z-index:4;" class="SearchBox"><input type="text" id="sbSourceCharacteristicValues" onkeyup="lstSourceCharacteristicValuesSearch()"></div></div>
</div>