Workaround to translate the "Please enter a valid emial address." message to German when "/l/ger/" is in the URL. Other languages can be done, too. Simply change the text for "/l/ger/" and the translated `message` variable.

invalid_email_german.html

<script type="text/javascript">

    // SalsaStaff 114865: replace the email validation function with one
    // that shows a mesage in German when the email address is invalid and
    // the URL contains '/l/ger/'. The default is to show the standard
    // Enlish message.
    // Note: This script must appear *after* the teplate tags.
    function validateEmail() 
    {
        var email = $(this).attr('email');
        if (email=="") return;
        var re =/^[_a-zA-Z0-9!#$%&'*+/=?^`{|}~-]+(\.[_a-zA-Z0-9&'!#$%&'*+/=?^`{|}~-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]{1,})*\.([a-zA-Z]{2,}){1}$/;
        
        if (! re.test(email) ){
            var message = 'Please enter a valid email address.';
            if (window.location.href.indexOf('/l/ger/') !== -1) {
                message = 'Bitte eine korrekte Email-Adresse eingeben.';
            }
            $("div[id='emailValidationErrorId']").html("<span class='required'>"
                + message
                + "</span>");
            return false;
        }else{
            $("div[id='emailValidationErrorId']").html("");
            return true;
        };
    }
    $(document).ready(function() {
        var e = $('input[name=Email]');
        if (e.length == 0) return;
        e.unbind('blur');
        e.blur(validateEmail);
    });
</script>