function getDateFormatted(date) {
  var day = date.getDate();
  var month = date.getMonth() + 1;
  var year = date.getFullYear();
  var ret = "";
  ret += (day < 10) ? "0" + day : day;
  ret += "/";
  ret += (month < 10) ? "0" + month : month;
  ret += "/";
  ret += year;
  return ret;
}

function fillDateInputs() {
  var dateFin = "";
  var dateDebut = "";

  var i = document.Choix.filtre.selectedIndex;
  var value = document.Choix.filtre.options[i].value;
  if (value.substr(1) == 'dmois') {
    var moisCount = Number(value.substr(0, 1));
    var dateFinDate = new Date();
    var dateDebutDate = new Date();
    dateDebutDate.setMonth(dateFinDate.getMonth() - moisCount);
    dateDebut = getDateFormatted(dateDebutDate);
    dateFin = getDateFormatted(dateFinDate)
    Date;
  }

  document.Choix.date_debut.value = dateDebut;
  document.Choix.date_fin.value = dateFin;
}