function checkForm (formControl) {
  var form = formControl;

  //check required fields for email-delivery
  if ( form.report[0].checked == true ) {
    if (form.name.value == "") {
      alert ("Please enter your name.");
      form.name.focus();
      return;
    }
    if (  form.mail.value == "" || form.mail.value.indexOf('@', 0) == -1 || !form.mail.value.indexOf('.', 0)) {
      alert ("Please enter a valid e-mail address.");
      form.mail.focus();
      return;   
     }
  }
  
  //check required fields for post-delivery
  else {
    if (form.name.value == "") {
      alert ("Please enter your name.");
      form.name.focus();
      return;
    }
    if (form.company.value== "") {
      alert ("Please enter your company.");
      form.company.focus();
      return;
    }
    if (form.street.value == "") {
      alert ("Please enter your street.");
      form.street.focus();
      return;
    }
    if (form.plz.value == "") {
      alert ("Please enter your ZIP Code.");
      form.plz.focus();
      return;
    } 
    if (form.city.value == "") {
      alert ("Please enter your city.");
      form.city.focus();
      return;
    }
    if (form.country.value == "") {
      alert ("Please enter your country.");
      form.country.focus();
      return;
    }
  }

  form.submit();

}

// Find an element in IE 4, Opera, or Mozilla.
function fetchById(id) {
  return document.getElementById ? document.getElementById(id) : document.all[id];
}

//show required fields for post-delivery
function show_req_post() {
  fetchById('req_company').style.display='inline';
  fetchById('req_street').style.display='inline';  
  fetchById('req_country').style.display='inline';
  fetchById('req_ZIP').style.display='inline';
  fetchById('req_email').style.display='none';
}

//show required fields for email-delivery
function show_req_email() {
  fetchById('req_company').style.display='none';
  fetchById('req_street').style.display='none';  
  fetchById('req_country').style.display='none';
  fetchById('req_ZIP').style.display='none';
  fetchById('req_email').style.display='inline';
}