function klik (did,did2,did3) {
        if (document.getElementById(did).style.display == 'none')
        {
            toggle(did,'display','show');
            toggle(did2,'display','hide');
            toggle(did3,'display','hide');
        }
        else
        {
            toggle(did,'display','hide');
            toggle(did2,'display','hide');
            toggle(did3,'display','hide');
        }
    }


function toggle(layer,kind,task) {

    if (kind=="visibility"){
        if (task=="hide")
            vis_to = "hidden";
        else if (task=="show")
            vis_to = "visible";
        else {

            if (document.layers)
                vis_to = (document.layers[layer].visibility=="hide") ? "show" : "hide";

            else if (document.all)
                vis_to = (document.all[layer].style.visibility=="hidden") ? "visible" : "hidden";

            else if (document.getElementById)
                vis_to = (document.getElementById(layer).style.visibility=="hidden") ? "visible" : "hidden";
        }
    } else if (kind=="display"){
        if (task=="hide")
            dis_to = "none";
        else if (task=="show")
            dis_to = "block";
        else {
            if (document.layers)
                dis_to = (document.layers[layer].display=="none") ? "block" : "none";

            else if (document.all)
                dis_to = (document.all[layer].style.display=="none") ? "block" : "none";

            else if (document.getElementById)
                dis_to = (document.getElementById(layer).style.display=="none") ? "block" : "none";
        }
    }

    if (document.layers)
        (kind=="display") ? document.layers[layer].display = dis_to : document.layers[layer].visibility = vis_to;

    else if (document.all)
        (kind=="display") ? document.all[layer].style.display = dis_to : document.all[layer].style.visibility = vis_to;

    else if (document.getElementById)
        (kind=="display") ? document.getElementById(layer).style.display = dis_to : document.getElementById(layer).style.visibility = vis_to;
}