Found by myself.
Using OnSave event and "e.event.set()"
function scheduler_save(e) {
var _fournisseur = $('#FournisseurCBB').val();
if (!checkFournisseur(_fournisseur, e.event)) {
e.preventDefault();
}
var _title = $('#txtTitre').val();
e.event.set("title", _title);
}