function isEmpty(elem) {
        if (elem.value == "") {
            alert("Please fill out the required field " + elem.name);
            elem.focus();
            return true;
        }
        return false
    }
    function formOK() {
        /*
            To add another required field.
                The name of the form is contact, the name
                of the textfield changes in each instance.
                Simply cut or copy, then paste changing the name
                of the text field you wish to check in each case.

        */
        if ((isEmpty(document.contact.Name)) ||
            (isEmpty(document.contact.StreetAddress)) ||
            (isEmpty(document.contact.Address2)) ||
            (isEmpty(document.contact.County)) ||
            (isEmpty(document.contact.PostCode))) {
            
                    // form has a problem
                    return false;
            }
            return true;
    }