how to get javascript variable value in GATLING

I have a response body and i need some spesific javascript value in that.(__processUniqueID) How i can do ?

Gatling 2.3.1 version

<script type="text/javascript">
var __processUniqueID = '06c199ab-**********';
var __isDocument = false;
var __isDMSDifference = false;
var __hasSanction = false;
</script>

I want to output "06c199ab-**********".