PageSpeed defer javascript example

deferJs.html

<script>

	// Add a script element as a child of the body
	function downloadJSAtOnload() {
		var element = document.createElement("script");
		element.src = "deferredfunctions.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>