function switchtabs(t) {
    // 4 is 1 + the number of tabs
    // each tab content area is named tab1, tab2 etc..
    // each tab head is named thead1, thead2 etc...
    try {
        for (i = 1; i < 6; i++) {

            el = document.getElementById("tab" + i);
            elhead = document.getElementById("thead" + i);
            if (i == t) {
                el.style.display = "";
                elhead.className = "current";
            }
            else {
                el.style.display = "none";
                elhead.className = "";
            }
        }

    }
    catch (ErrorObject)
    { }
}