function showsubmenu(sid)
    {
        whichEl = eval("submenu" + sid);
        if (whichEl.style.display == "none")
            {
                eval("submenu" + sid + ".style.display=\"\";");
                eval("document.all.b_" + sid + ".src=\"imgaes/subtraction.gif\";");
            }
        else
            {
                eval("submenu" + sid + ".style.display=\"none\";");
                eval("document.all.b_" + sid + ".src=\"imgaes/add.gif\";");  
            }
    }