Jquery query string value

<p class="lead">Add a "?q=XXXX" at the end of the URL and you will see the value here.</p>
<b>Value: <span id="insert-value">UNDEFINED</span></b>

</br></br></br>
I would rather the value in the input and disappear when you click the input</br>
<input type='text' name='q' id='searchthat' class='custom_input_inside message'>

<script src="jquery-3.4.1.min.js"></script>
<script src="https://code.jquery.com/jquery-3.2.1.slim.js"/></script>
    <script>
!(function (e) {
    e.extend({
        uriGet: function () {
            var e = location.href,
                t = new URL(e),
                n = t.searchParams.get(arguments[0]);
            return n;
        },
    });
})(jQuery);

    $( document ).ready(function() {
      var a = $.uriGet('q');
      $('span#insert-value').html(a);//if you change that to input it wont work.  I want it to triggure in the input field only would be better if it will by css in the input
    let inputEle = $("#searchthat");
    inputEle.val(a);
    inputEle.on("focus",function(){
      inputEle.val("");
    });

  });
    </script>