function af(n){if (document.getElementById(n)){document.getElementById(n).style.visibility = "visible";}}

function bt(n){if (document.getElementById(n)){document.getElementById(n).className='bt_info_on';}}
function bt2(n){if (document.getElementById(n)){
document.getElementById(n).className='bt_info_big_on';}

}
function bt3(n){if (document.getElementById(n)){document.getElementById(n).className='bt_info2_on';}}
//cache le calque
function fa(n){document.getElementById(n).style.visibility="hidden";}
function tb(n){if (document.getElementById(n)){document.getElementById(n).className='bt_top';}}
function tb2(n){if (document.getElementById(n)){document.getElementById(n).className='bt_top_big';}}