<p>Username:<br />
                <h:inputText id="username"
                             value="#{AccountController.account.userName}"
                             required="true"
                             requiredMessage="A name is required."
                             maxlength="25">
                    <f:ajax event="keyup" render="availability" listener="#{AccountController.availabilityListener}" />
                </h:inputText>
                <h:outputText id="availability" value="#{AccountController.availability}" />
            </p>