function changeTab(index, count) {

    for (i = 1; i <= count; ++i) {
        var tab = document.getElementById("tab" + i);
        var link = document.getElementById("link" + i);

        if (i == index) {
            tab.style.display = "";
            link.className = "active";
        }
        else {
            tab.style.display = "none";
            link.className = "";
        }
    }
        
}