Javascript Motion Tween

[Fashoomp]

Hi there,

I'm trying to figure out the Java Motion tween found on this site.
It's for a class project due in 2 days, and I'm trying to have a link on my webpage tween in a div. The div is already visible on the screen, and I just want it to drop down 125 pixels. My js function is:

function showInfo (myVar){
	var tweenIn = new Tween (document.getElementById(myVar), 'top', Tween.strongEaseOut, 75, 200, 5, 'px');
	tweenIn.start();
}

I call the function in the html with onclick="showInfo('mainimage')"
where 'mainimage' is the div that I want to drop in. I'm positive my js files are linked properly.

If anyone has any experience with this, I'd greatly appreciate some assistance.