Quiz js from http://www.reddit.com/r/learnjavascript/comments/27ioma/would_like_some_kind_folks_to_critique_my/

quiz.js

//    Important updates:
// #6 - load function works as intended
// #8 - core functionality works with loading questions and calculating scores
// #9 - completion of task

var Quiz = {

  questions: [
    {title: "How many hairs are on a pony?", choices: ["0", "1", "2", "More than two"], correctAnswer: 3},
    {title: "Who lives in the Barbie Dream House?", choices: ["Barbie & Ken", "Peter & Mary", "Ben & Jerry", "It is an empty house"], correctAnswer: 0}
  ],

  init: function() {

    this.button = document.getElementById("btn-next");
    this.button.addEventListener("click", this.onButtonClick.bind(this), false);

    this.radios         = document.querySelectorAll("input[type='radio']");
    this.h2             = document.querySelector("h2");
    this.form           = document.getElementById("myForm");
    this.labels         = document.getElementsByTagName("label");
    this.score          = 0;
    this.questionNumber = 0;

    this.nextQuestion();
  },

  nextQuestion: function() {
    var question = this.questions[this.questionNumber];

    if (this.h2.firstChild) {
      this.h2.firstChild.data = question.title;
    } else {
      this.h2.appendChild(document.createTextNode(question.title));
    }

    for (var i = 0, l = question.choices.length; i < l; i++) {
      this.form.elements[i].setAttribute("name", "question");
      this.form.elements[i].value = question.choices[i];
      this.labels[i].htmlFor = question.choices[i];
      if (this.labels[i].firstChild) {
        this.labels[i].firstChild.data = question.choices[i];
      } else {
        this.labels[i].appendChild(document.createTextNode(question.choices[i]));
      }
    }
  },

  displayScore: function() {
    var container = document.querySelector(".container");
    container.removeChild(this.button);
    container.removeChild(this.form);

    var h1 = document.createElement("h1");
    h1.textContent = "Your score is: " + this.score.toString();

    container.appendChild(h1);
  },

  onButtonClick: function(e){
    for (var i = 0, l = this.radios.length; i < l; i++) {
      if (this.radios[i].checked) {
        this.score += +(i === this.questions[this.questionNumber].correctAnswer) * 10;
        this.radios[i].checked = false;
        break;
      }
    }
    if (++this.questionNumber === this.questions.length) {
      this.displayScore();
    } else {
      this.nextQuestion();
    }
    return false;
  }

};

document.addEventListener("DOMContentLoaded", function() {
  Quiz.init();
}, false);