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...
    for (i=1;i < 7;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 = "";
        }
    }

}