function doClick(index, numTabs, id, stylefront, styleback)
    {
        document.getElementById("tab" + id + index).className = stylefront;
        for (var i=1; i < numTabs; i++)
        {
            document.getElementById("tab" + id + ((index + i) % numTabs)).className = styleback;
        }
        document.getElementById("code" + id + index).style.display = "";
        for (var j=1; j < numTabs; j++)
        {
          document.getElementById("code" + id + ((index + j) % numTabs)).style.display = "none";
        }
    }