// for Mozilla browsers
if (document.addEventListener) {
document.addEventListener("DOMContentLoaded", init, false);
}

<script defer type="text/javascript">
alert("DOM 加載完畢！")
</script>

<!--[if IE]>
<script defer type="text/javascript">
alert("DOM 加載完畢！")
</script>
<![endif]-->

<script defer type="text/javascript">
// for Internet Explorer
/*@cc_on @*/
/*@if (@_win32)
alert("DOM 加載完畢！");
/*@end @*/
</script>

if (/WebKit/i.test(navigator.userAgent)) { // sniff
var _timer = setInterval(function() {
if (/loaded|complete/.test(document.readyState)) {
clearInterval(_timer);
init(); // call the onload handler
}
}, 10);
}