function show(object) {
    if (document.getElementById && document.getElementById(object) != null)
         node = document.getElementById(object).style.visibility='visible';
    else if (document.layers && document.layers[object] != null)
        document.layers[object].visibility = 'visible';
    else if (document.all)
        document.all[object].style.visibility = 'visible';
}

function hide(object) {
    if (document.getElementById && document.getElementById(object) != null)
         node = document.getElementById(object).style.visibility='hidden';
    else if (document.layers && document.layers[object] != null)
        document.layers[object].visibility = 'hidden';
    else if (document.all)
         document.all[object].style.visibility = 'hidden';
}

function openfile(file) {
    if (document.getElementById)
         document.getElementById('main').src=file;
    else if (document.layers)
        document.getElementById('main').src=file;
    else if (document.all)
        window.frames('main').document.location.href=file;
}