function DropDownMenu(parent) {
    Element.extend(parent);
  
    // parent is the <li> that contains the <ul>
    var $subMenu = parent.down('ul');
    var $anchor = parent.down('a');

    $anchor.addClassName('DropDownSelected');
    
    $subMenu.show();   
        
    var $width = $subMenu.down('li').getWidth();
    var $anchorWidth = $anchor.getWidth();
    
    var $parentHeight = $(parent.parentNode).getHeight();        
    
    var $offset = Position.cumulativeOffset(parent);
    var $left = parent.offsetLeft  + ($anchorWidth / 2) - ($width /2);
    var $top = $parentHeight;
                
    $subMenu.setStyle({        
        left: $left + 'px'        
    });
}

function CloseUpMenu(parent) {
    Element.extend(parent);
    var $submenu = parent.down('ul');

    parent.down('a').removeClassName('DropDownSelected');

    $submenu.setStyle({ left: '-999em' });
}