how to get search query from datatable code example

Example: datatable search

<link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/1.10.23/css/jquery.dataTables.css">
  
<script type="text/javascript" charset="utf8" src="https://cdn.datatables.net/1.10.23/js/jquery.dataTables.js"></script>