function checkFields() {
missinginfo = "";
if (document.form.Firma.value == "") {
missinginfo += "Firma, ";
}
if (document.form.Besteller.value == "") {
missinginfo += "Besteller\n";
}
if (document.form.Baustelle.value == "") {
missinginfo += "Baustelle, ";
}
if (document.form.Lieferdatum.value == "") {
missinginfo += "Lieferdatum\n";
}
if (document.form.Betonierbeginn.value == "") {
missinginfo += "Betonierbeginn, ";
}
if (document.form.Menge.value == "") {
missinginfo += "Menge, ";
}
if (document.form.Abnahme.value == "") {
missinginfo += "Abnahme/Stunde\n";
}
if (document.form.Sortennummer.value == "") {
missinginfo += "Sorten Nr, ";
}
if (document.form.Betonguete.value == "") {
missinginfo += "Betonguete, ";
}
if (document.form.Zusatzmittel.value == "") {
missinginfo += "Zusatzmittel\n";
}
if (document.form.Verzoegerungszeit.value == "") {
missinginfo += "Verzoegerungszeit, ";
}

if (document.form.Strasse.value == "") {
missinginfo += "Strasse, ";
}
if (document.form.PLZ.value == "") {
missinginfo += "PLZ, ";
}
if (document.form.Ort.value == "") {
missinginfo += "Ort\n";
}
if (document.form.Telefon.value == "") {
missinginfo += "Telefon, ";
}
/*if (document.form.Telefax.value == "") {
missinginfo += "Telefax, ";
}
if ((document.form.email.value == "") || 
(document.form.email.value.indexOf('@') == -1) || 
(document.form.email.value.indexOf('.') == -1)) {
missinginfo += "email";
}*/
if (missinginfo != "") {
missinginfo ="_____________________________\n" +
"Um Ihre mail beantworten zu koennen,\ngeben Sie bitte folgende Angaben ein:\n" +
missinginfo + "\n_____________________________";
alert(missinginfo);
return false;
}
else return true;
}