function roll_over(img_name, img_src){
   document.getElementById(img_name).src = img_src;
}

function FValidateControl(control) {
  if (control.value=="") {
    alert(control.name+" nog invullen a.u.b.");
    control.focus();
    return false;
  }
  return true;
}

function FSubmitValidation(form) {

  if (!FValidateControl(form.Bedrijfsnaam)) 
    return false;
  if (!FValidateControl(form.Adres)) 
    return false;
  if (!FValidateControl(form.Postcode)) 
    return false;
  if (!FValidateControl(form.Plaats)) 
    return false;
  if (!FValidateControl(form.Kontaktpersoon)) 
    return false;
  if (!FValidateControl(form.Telefoon)) 
    return false;
  
  if (!FValidateControl(form.Email)) 
    return false;
  if (!FValidateControl(form.Merk)) 
    return false;
  if (!FValidateControl(form.Type)) 
    return false;
  
  return true;
}