function chkFormular () {
    if (document.form1.emailadresse.value  == "") {
    alert("Please state your e-mail address!");
    document.form1.emailadresse.focus();
    return false;
  }
  if (document.form1.name.value == "") {
    alert("Please state your name!");
    document.form1.name.focus();
    return false;
  }
     if (document.form1.anzahl_kinder.value > 0) {
   if (document.form1.alter.value == "") {
    alert("Please state age of children separated by commas!");
    document.form1.alter.focus();
    return false; }
  }
}