Javascript create text/javascript using var

Javascript: create script type = 'text-javascript' using var

<script>
             $( document ).ready(function() {
               //create a script element and set it's type and async attributes
               var script = document.createElement('script'); script.type = 'text/javascript'; script.async = true;

                //set the source of the script element
                script.src = 'https://widgets.quadpay.com/stfrank/quadpay-widget-0.2.0.js?type=calculator&min=1&max=2500';

               //add the script element to the DOM
               var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(script, s);


              //~initialise what you want~

             });
           </script>