function software_show_popup_menu(parent_element, position)
{
    parent_element.className = 'on';

    // loop through all nodes under li, in order to find a menu
    for (var i = 0; i < parent_element.childNodes.length; i++) {
        var node = parent_element.childNodes[i];
        
        // if node is a ul, then position menu and show menu
        if (node.nodeName == 'UL') {
            switch (position) {
                case 'Top':
                    node.style.left = '0';
                    node.style.top = '-' + node.offsetHeight + 'px';
                    break
                        
                case 'Bottom':
                    node.style.left = '0';
                    node.style.top = node.parentNode.offsetHeight + 'px';
                    break
                        
                case 'Left':
                    node.style.left = '-' + node.offsetWidth + 'px';
                    node.style.top = '0';
                    break;
                    
                case 'Right':
                    node.style.left = node.parentNode.offsetWidth + 'px';
                    node.style.top = '0';
                    break;
            }
            
            node.style.visibility = 'visible';
        }
    }
}

function software_hide_popup_menu(parent_element)
{
    parent_element.className = '';
    
    // loop through all nodes under li, in order to find a menu
    for (var i = 0; i < parent_element.childNodes.length; i++) {
        var node = parent_element.childNodes[i];
        
        // if node is a ul, then hide menu
        if (node.nodeName == 'UL') {
            node.style.visibility = 'hidden';
        }
    }
}