function show_intro(pre, pree, n, select_n) {
    for (i = 1; i <= n; i++) {
        var intro = document.getElementById(pre + i);
        var cha = document.getElementById(pree + i);
        intro.style.display = "none";
        cha.className = "pinpai_off";
        if (i == select_n) {
            intro.style.display = "block";
            cha.className = "pinpai_on";
        }
    }
}

function p$(string) {
    document.write(string);
}
function $(id) {
    return document.getElementById(id);
}
function change_menu(id, content_id, num, total_ztc_menu, menu_on, menu_off) {
    for (var i = 1; i <= total_ztc_menu; i++) {
        $(id + i).className = menu_off;
        $(content_id + i).style.display = 'none';
    }
    $(id + num).className = menu_on;
    $(content_id + num).style.display = 'block';
}