function switch_layer5(id)
{
    var maincell = document.getElementById("main5");
    var layerlist = maincell.getElementsByTagName("div");

    var i = 0;
    for (i = 0; i < layerlist.length; i++)
    {
        layerlist[i].className = "clayer_hidden";
    }

    document.getElementById(id).className = "clayer_shown";
}

function switch_layer6(id)
{
    var maincell = document.getElementById("main6");
    var layerlist = maincell.getElementsByTagName("div");

    var i = 0;
    for (i = 0; i < layerlist.length; i++)
    {
        layerlist[i].className = "clayer_hidden";
    }

    document.getElementById(id).className = "clayer_shown";
}

function switch_layer7(id)
{
    var maincell = document.getElementById("main7");
    var layerlist = maincell.getElementsByTagName("div");

    var i = 0;
    for (i = 0; i < layerlist.length; i++)
    {
        layerlist[i].className = "clayer_hidden";
    }

    document.getElementById(id).className = "clayer_shown";
}