counter 1: increment ( ajax-only link )
counter 2: increment ( ajax fallback link. this link uses ajax when it is available, and a regular wicket roundtrip when ajax or javascript are not available. )
counter 3: increment ( ajax link with a busy indicator. the server will deliberately pause for five seconds. both ajax-only and fallback versions exist. )
onSuccess script: success (will trigger the onsuccess javascript)
onFailure script: failure (will trigger the onfailure javascript)
break out of ajax and redirect to a new page: redirect
test exception handling (should display an error page): exception