$(document).ready(function() { 
 
    $('#btn-submit').click(function() {  
 
        $(".error").hide();
        var hasError = false;
        var emailReg = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/;
 
        var emailaddressVal = $("#email").val();
        if(emailaddressVal == '') {
            $("#email").before('<span class="error">Vul a.u.b. uw e-mailadres in.</span>');
            hasError = true;
        }
 
        else if(!emailReg.test(emailaddressVal)) {
            $("#email").before('<span class="error">Vul a.u.b. een geldig e-mailadres in.</span>');
            hasError = true;
        }
         var naamVal = $("#naam").val();
        if(naamVal == '') {
            $("#naam").before('<span class="error">Vul a.u.b. uw naam in.</span>');
            hasError = true;
        }

        if(hasError == true) { return false; }
 
    });
});