sample_handler.js

function theNameOfYourCallbackFunction(quiz){
  quiz.on('question:enter', function(){
    refreshAdWhenQuestionChanges();
  });
  quiz.on('result:enter', function(result){
    if (result.title == 'My Result') {
      handleMyResultSpecial();
    } else if (result.score < 25) {
      handleTerribleScore();
    } else {
      handleAllOtherResults();
    }
  });
}