function show(divId) {
    elems = document.getElementsByTagName("div");
    r = /div(\d+)/i;
    for (i = 0; i < elems.length; i++) {
        arr = r.exec(elems[i].id);
        if (arr != null && arr.length > 1) {
            elems[i].className = 'hidden';
        }
    }
    document.getElementById(divId).className = "";
}