Hide And Show Div On Page Load

I am trying to use javascript to hide a div before the page loads. Unfortunately for a brief second I can see the div on the page before the java script hide it. Is there anyway to set the javascript to hide the div before the page completely loads?

<script type="text/javascript" src="prototype.lite.js"></script>
<script type="text/javascript" src="moo.fx.js"></script>
<script type="text/javascript" src="moo.fx.pack.js"></script>
<script type="text/javascript">
var forgotpass = document.getElementsByClassName('forgotpass');
window.onload = function() {
forgotpass = new fx.Combo('forgotpass', {height: true, opacity: true, duration: 500});

// Hide Div
forgotpass.hide();

}
</script>

P.S. I'm using the hide function within the moo.fx.js file found @ http://moofx.mad4milk.net/. If there is an easier way to di by just write the javascript out in the onload function please let me know.