function menuOverOut( id )
{
	var els = document.getElementById(id).getElementsByTagName('li');
	var nels = els.length;

	for (var i=0; i < nels; i++)
	{
		var el = els[i];

			el.onmouseover = function()
			{
				this.className = this.id+"Over";
			}

			el.onmouseout = function()
			{
				this.className = "";
			}
	}
}

menuOverOut('mainMenuTop');