function hide() {
    var elem;
    for (var i = 1; i < 11; i++) {
        elem = getElement('m' + i + 'on');
        if (elem) elem.style.display = "none";    
        elem = getElement('m' + i + 'off');
        if (elem) elem.style.display = "block";
     }
     elem = getElement('menu_tail_on');
     elem.style.display = "none";
     elem = getElement('menu_tail_off');
     elem.style.display = "block";
}

function show( item ) {
    hide();
    elem = getElement(item + 'on');
    if (elem) elem.style.display = "block";    
    elem = getElement(item + 'off');
    if (elem) elem.style.display = "none";
    
}

function getElement( elName ) {
    // Get an element from its ID
    if (document.all)
        return document.all[elName];
    if (document.layers)
        return document.layers[elName];
    if (document.getElementById) {
        return document.getElementById(elName);
    }
}