function submitForm(e) {
    new Ajax.Request($('win_form').getAttribute('action'), {
        method: 'post',
        parameters: $('win_form').serialize(true),
        onSuccess: function(transport){
            if(transport.responseText.isJSON()) {
                var errors = transport.responseText.evalJSON(true);
            } else {
                var errors = '{}'.evalJSON(true);
                $('win_form').replace('Bedankt voor je inzending!');
            }
            $$('#win_form label').each(function(el) {
                var forValue = el.getAttribute('htmlFor') || el.getAttribute('for');
                if (errors[forValue.replace('win_', '')]) {
                    el.highlight({ startcolor: '#ffafaf', endcolor: '#ffffff' });
                    el.className = 'error';
                } else {
                    el.removeClassName('error');
                }
            });
        }
    });
    Event.stop(e);
}
Event.observe(window, 'load', function(){Event.observe($('win_form'), 'submit', submitForm, false)}, false);