function twValide_date(nDate,nA1,nA2,nFormat) {
  // Ajouter ce code dans la saisie du champs date
  //  onBlur="twValide_date(this,1950,2020,'jj/mm/aaaa')"
  // La date valide doit être entre 1950 et 2020.
  //    vous pouvez changer l'interval.
  // Format valide: (ne pas utiliser d'autre format...
  // - jj/mm/aaaa
  // - mm/jj/aaaa
  // - aaaa/mm/jj
  // Noter que vous devriez indiquer à l'usager le format valide...
  var ok = "oui";
  var nChar;
  var aDate;
  var nJ;
  var nM;
  var nA;
  var jMax = 31;
  nAccepte = "0123456789/";
  if (nDate.value.length > 0) {
    if (nDate.value.length < 8 || nDate.value.length > 10) ok = "non";
    for (var i=0; i<nDate.value.length; i++) {
      nChar = "" + nDate.value.substring(i, i+1);
      if (nAccepte.indexOf(nChar) == "-1") ok = "non";
    }
    if (ok == "oui") {
      aDate = nDate.value.split("/");
      if (nFormat == "jj/mm/aaaa") { nJ = aDate[0]; nM = aDate[1]; nA = aDate[2];
      } else if (nFormat == "mm/jj/aaaa") { nJ = aDate[1]; nM = aDate[0]; nA = aDate[2];
        } else if (nFormat == "aaaa/mm/jj") { nJ = aDate[2]; nM = aDate[1]; nA = aDate[0]; }
      if ((nJ < 1 || nJ > jMax) || (nM < 1 || nM > 12) || (nA < nA1 || nA > nA2)) ok = "non";
      else {
        if (nM == 2) { 
          if (AnneeBissex(nA) == true) { jMax = 29 } else { jMax = 28 }
        }
        if ((nM == 1 || nM == 3 || nM == 5 || nM == 7 || nM == 8 || nM == 10 || nM == 12)) jMax = 31
        if ((nM == 4 || nM == 6 || nM == 9 || nM == 11)) jMax = 30
        if (nJ < 1 || nJ > jMax) ok = "non";
      }
    }
    if (ok == "non") {
      nDate.focus();
      nDate.select();
      if (nlang=="fr") 
        alert ("\nDate invalide ! Veuillez entrer une date valide sous le format suivant : "+nFormat+"\nentre "+nA1+" et "+nA2)
      else 
        alert ("\nInvalid date. Please re-enter valid date: "+nFormat+"\nbetween "+nA1+" et "+nA2)
    }
  }
}