auto-click event on key events?

Why does an additional click event fire upon any key event? This has been observed in FF45

by Laberwurschd

HTML

<body>
  <main>
    <h1>My Quiz</h1>
    <p>Here could be a quiz...</p>
    <section id="quiz"></section>
  </main>
</body>

JavaScript

var myQuiz = {
  container: null,

  // helper function
  createElement: function(o) {
    var el, p;

    if (o && (o.tag || o.tagName)) {
      el = document.createElement(o.tag || o.tagName);

      if (o.text || o.txt) {
        el.appendChild(
          document.createTextNode(o.text || o.txt)
        );
      }

      for (p in o) {
        if (!p.match(/^t(e)?xt|tag(name)?$/i)) {
          el[p] = o[p];
        }
      }
    }

    return el;
  },

  // user interface for a quiz question
  createOptions: function() {
    var t = this,
      ul = document.createElement("ul");

    t.emptyContainer();

    t.intoContainer(t.createElement({
      tag: "h1",
      text: t.currentQuestion.getQuestion()
    }));

    t.intoContainer(ul);

    t.currentQuestion.getOptions().forEach(function(s, i) {
      var li = document.createElement("li"),
        label = t.createElement({
          tag: "label",
          text: s
        }),
        radio = t.createElement({
          name: "anwer",
          tag: "input",
          type: "radio",
          value: s
        });

      ul.appendChild(li);
      li.appendChild(label);
      label.insertBefore(radio, label.firstChild);
    });

    // Hinweis für Tastatur-User
    t.intoContainer(t.createElement({
      tag: "p",
      text: "If using the keyboard please use the enter key to finalize your choice."
    }));
  },

  currentQuestion: null,

  // data could be filled from an external source (JSON)
  data: [{
    question: "What is Germany's capital?",
    solution: "Berlin",
    falses: ["Hamburg", "München", "Hannover"]
  }, {
    question: "Who is currently Germany's head of state?",
    solution: "Angela Merkel",
    falses: ["Joachim Gauck", "Sigmar Gabriel", "Norbert Lammert"]
  }],

  emptyContainer: function() {
    var t = this;

    while (t.container.firstChild) {
      t.container.removeChild(t.container.firstChild);
    }
  },

  handleInput: function(ev) {
    var t = this, // t points to myQuiz
     ...