load jquery after page load

https://github.com/danriti/bootstrap-pagespeed/commit/50e10b6a908d71fa8b79b153c36042a5d29efe1b

<script type="text/javascript">
+    // Add a script element as a child of the body
+    function downloadJSAtOnload() {
+    var element = document.createElement("script");
+    element.src = "scripts/all.min.js";
+    document.body.appendChild(element);
+    }
+
+    // Check for browser support of event handling capability
+    if (window.addEventListener)
+    window.addEventListener("load", downloadJSAtOnload, false);
+    else if (window.attachEvent)
+    window.attachEvent("onload", downloadJSAtOnload);
+    else window.onload = downloadJSAtOnload;
+    </script>