/* sub_01 */
function hide_sub_01()
{ document.getElementById('sub_01').style.visibility = "hidden"; }
function show_sub_01()
{ document.getElementById('sub_01').style.visibility = "visible"; }

/* sub_01_01 */
function hide_sub_01_01()
{ document.getElementById('sub_01_01').style.visibility = "hidden"; }
function show_sub_01_01()
{ document.getElementById('sub_01_01').style.visibility = "visible"; }