$(document).ready(function() { // nabinduji pouze pokud tuto zalezitost nezajistuje checkForm
    $('input.nw_email').parents().each(function(){
        if ('form' == this.tagName.toLowerCase()) {
            var add_check = true;
            var check_handler = "checkForm";            
            var events = $(this).data('events');
            var form_onsubmit = $(this).attr('onsubmit');
            
            if (events != null && "submit" in events) {
                jQuery.each(events.submit, function(i, event){
                    jQuery.each(event, function(i, handler){
                        if (handler !== null && handler.toString().indexOf(check_handler) != -1) {
                            add_check = false;
                        }
                    });
                });
            }

            if (add_check && (form_onsubmit == null || form_onsubmit.indexOf(check_handler) == -1)) {
                $(this).bind('submit', checkEmail);
            }
            
            return; // vyskocenu z cyklu each po nalezeni rodicovskeho formulare
        }    
    });
});

function checkEmail()
{
    var email_reg = /^([a-zA-Z0-9_.-])+@(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/;
    var emails = $(this).find('input.nw_email');
    var res = true;

    for (i = 0; i < emails.length; i++) {
        email = $(emails[i]).val();
        res = res && email_reg.test(email);
    }

    if (false == res) {
        alert('Emailová adresa musí být korektně zadána.');
    }

    return res;
}