var DropdownMenu = Class.create();
DropdownMenu.prototype =
{
    initialize : function(menuNode)
    {
        var dropdowns = menuNode.getElementsByTagName('li');

        for(var i = 0; i < dropdowns.length; i++)
		{
			but = dropdowns[i];
            but.onmouseover = function()
            {
                var uls = this.getElementsByTagName('ul');

                for(var b = 0; b < uls.length; b++)
                {

                    if(uls[b].nodeName == 'UL')
                    {
                        uls[b].style.display="block";
                        break;
                    }
                    Element.addClassName(this, 'over')
                }
            }
            but.onmouseout  = function()
            {
                var uls = this.getElementsByTagName('ul');

                for(var b = 0; b < uls.length; b++)
                {

                    if(uls[b].nodeName == 'UL')
                    {
                        uls[b].style.display="none";
                        break;
                    }
                    Element.removeClassName(this, 'over')
                }
            }
		}
    }
}

Event.observe(window, 'load', function()
{
        ClassObject.assign('top-nav', DropdownMenu);
});

var ClassObject=
{
	assign:function(className,objectCopy)
	{
		var elements=document.getElementsByClassName(className);
		if(typeof elements!='undefined')
		{
			for(var i=0;i<elements.length;i++)
			{
				new objectCopy(elements[i]);
			}
		}
	}
}