function checkRequiredFields(input)
{
    var requiredFields = new Array("nachricht","email");
    var fieldNames = new Array("Nachricht","E-mail");

    var fieldCheck   = true;
    var fieldsNeeded = "\nIn diesem Formular müssen Sie alle Felder ausfüllen! Bitte\nFüllen Sie folgende noch leere Felder aus:\n\n\t";

    for(var fieldNum=0; fieldNum < requiredFields.length; fieldNum++) {
        if ((input.elements[requiredFields[fieldNum]].value == "") ||
            (input.elements[requiredFields[fieldNum]].value == " ")||
            (input.elements[requiredFields[fieldNum]].value == "Bitte w&auml;hlen...")) {

            fieldsNeeded += fieldNames[fieldNum] + "\n\t";
            fieldCheck = false;
        }
    }
    if (fieldCheck == true)
    {
        return true;
    }
    else
    {
        alert(fieldsNeeded);
        return false;
    }
}