function cocheDecocherTout(boutonID) {
    selection = !selection;
    var liste = document.getElementsByTagName("input");
    for (i = 0; i<liste.length; i++) {
        if (liste[i].type == "checkbox") {
            liste[i].checked = selection;
        }
    }
    var btn = document.getElementById(boutonID);
    btn.value = selection ? toutDeselect : toutSelect;
}