Troubleshooting Redirect

I am using the following redirect script installed in the header section of my 2013 Theme:

<script type="text/javascript">function downloadJSAtOnload(){var element = document.createElement("script");element.src = "http://my.accessmobilewebsite.com/js/switcher.js.php?id=19157";document.body.appendChild(element);}if (window.addEventListener)window.addEventListener("load", downloadJSAtOnload, false);else if (window.attachEvent)window.attachEvent("onload", downloadJSAtOnload);else window.onload = downloadJSAtOnload;</script>

To redirect to my mobile website. Please help me know what to fix.