init javascript with require.js after page loaded

<script type="text/javascript">
        if(window.applicationCache){
            window.applicationCache.addEventListener("error", function(e) {
                document.body.innerHTML = "Error fetching manifest: a good chance we are offline";
            });
        }

        function init() {
            var rjs = document.createElement("script"); rjs.src = "/assets/lib/require.js"; document.body.appendChild(rjs);
            var timer = setInterval(function(){ if(window.require) { require(["/init.js"]); clearInterval(timer); } }, 1);
        }

        if (window.addEventListener)
            window.addEventListener("load", init, false);
        else if (window.attachEvent)
            window.attachEvent("onload", init);
        else window.onload = init;
    </script>