$(document).ready(function () {

    $('.signUp').click(function () {

        $(".error").hide();
        var hasError = false;
        var emailReg = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/;

        var emailaddressVal = $(".emailAddress").val();
        if (emailaddressVal == '') {
            hasError = true;
        }

        else if (!emailReg.test(emailaddressVal)) {
            hasError = true;
        }

        if (hasError == true) { jAlert("Pleas enter a valid e-mail address"); return false; }

    });
});