function toggleLayer(whichLayer,obj_name) {
    if (document.getElementById) {
        // this is the way the standards work
        var style2 = document.getElementById(whichLayer).style;
        style2.display = style2.display ? "" : "block";
        if (obj_name != null)
         hidelayer(obj_name);
        

    } else if (document.all) {
        // this is the way old msie versions work
        var style2 = document.all[whichLayer].style;
        style2.display = style2.display ? "" : "block";
    } else if (document.layers) {
        // this is the way nn4 works
        var style2 = document.layers[whichLayer].style;
        style2.display = style2.display ? "" : "block";
    }
}
function hidelayer(obj_name) {
    name = obj_name.substr(0, obj_name.lastIndexOf('_'));
    _siz = obj_name.substr(obj_name.lastIndexOf('_') + 1, 4);
    var num = _siz.substr(3, 1)
    siz = _siz.substr(0, 3);
    obj = document.getElementById(obj_name);

    if (siz == 'big') siz2 = 'sma'; else siz2 = 'big';
    obj2 = document.getElementById(name + '_' + siz2 + num);
    obj.style.display = 'none';
    obj2.style.display = 'block';
}