Event.observe($('item_name'), 'blur', function(event) {
    var element = Event.element(event);
    domainSearch.isDomainTaken(element.value, function(taken) {
        if (taken) {
            element.next().update('Lén er ekki laust').show();
        } else {
            element.next().update('').hide();
        }
    });
});