function checkFields()
                        {
                                missinginfo = "";
                                
                                if (document.form.firstname.value == "") 
                                {
                                        missinginfo += "\n   -  Voornaam";
                                }
                                if (document.form.lastname.value == "") 
                                {
                                        missinginfo += "\n   -  Naam";
                                }
                                if (document.form.street.value == "") 
                                {
                                        missinginfo += "\n   -  Straat";
                                }
                                if (document.form.housenumber.value == "") 
                                {
                                        missinginfo += "\n   -  Nr";
                                }
                                if (document.form.postcode.value == "") 
                                {
                                        missinginfo += "\n   -  Postcode";
                                }
                                if (document.form.country.value == "") 
                                {
                                        missinginfo += "\n   -  Land";
                                }
                                if ((document.form.email.value == "") || (document.form.email.value.indexOf('@') == -1) || (document.form.email.value.indexOf('.') == -1))
                                {
                                        missinginfo += "\n   -  Email adres";
                                }
                                if(document.form.birthdateString.value == "")
                                {
                                        missinginfo += "\n   -  Geboortedatum";
                                }
                                if (document.form.message.value == "") 
                                {
                                        missinginfo += "\n   -  Bericht";
                                }
                                
                                
                                
                                
                                
                                if (missinginfo != "")
                                {
                                        missinginfo ="Volgende velden zijn niet correct ingevuld:\n" + missinginfo;
                                        alert(missinginfo);
                                        return false;
                                }
                                else return true;
                        }