Aupajo/demo.html

## demo.html
  <!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Simple Quiz</title>
  </head>
  <body>

    <form action="/success-page" class="simple-quiz">
      <h3>Question 1</h3>

      <label>
        <input type="radio" name="answers[1]" value="A">
        Answer A
      </label>

      <label>
        <input type="radio" name="answers[1]" value="B">
        Answer B
      </label>

      <label>
        <input type="radio" name="answers[1]" value="C" data-correct>
        Answer C
      </label>

      <h3>Question 2</h3>

      <label>
        <input type="radio" name="answers[2]" value="A">
        Answer A
      </label>

      <label>
        <input type="radio" name="answers[2]" value="B" data-correct>
        Answer B
      </label>

      <label>
        <input type="radio" name="answers[2]" value="C">
        Answer C
      </label>

      <input type="submit">
    <form>

    <script src="jquery.js" type="text/javascript"></script>
    <script src="jquery.simpleQuiz.js" type="text/javascript"></script>

    <script type="text/javascript">
      $(document).ready(function() {
        $('.simple-quiz').simpleQuiz();
      });
    </script>
  </body>
</html>

## jquery.simpleQuiz.js
$.fn.every = function(callback) {
  var numElements = this.length;
  return this.filter(callback).length == numElements;
};

$.fn.simpleQuiz = function(options) {
  if(!this.length) { return; };

  this.each(function() {
    var form = $(this);
    var submitButton = form.find(':submit');
    var questions = form.find('.question');
    var choices = form.find(':radio');

    var init = function() {
      choices.on('change', answerChanged);
      form.on('submit', answersSubmitted);

      answerChanged();
    };

    var answersSubmitted = function(event) {
      if(!hasPassed()) {
        event.preventDefault();
        alert('Please try again.');
      }
    };

    var score = function() {
      return form.find(':checked[data-correct]').length;
    };

    var hasPassed = function() {
      return score() == questions.length;
    };

    var hasCheckedElement = function() {
      return $(this).has(':checked').length;
    };

    var allQuestionsAnswered = function() {
      return questions.every(hasCheckedElement);
    };

    var answerChanged = function() {
      if(allQuestionsAnswered()) {
        submitButton.removeAttr('disabled');
      } else {
        submitButton.attr('disabled', 'disabled');
      }
    };

    init();
  });

};
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>Simple Quiz</title>
	</head>
	<body>

	<form action="/success-page" class="simple-quiz">
	<h3>Question 1</h3>

	<label>
	<input type="radio" name="answers[1]" value="A">
	Answer A
	</label>

	<label>
	<input type="radio" name="answers[1]" value="B">
	Answer B
	</label>

	<label>
	<input type="radio" name="answers[1]" value="C" data-correct>
	Answer C
	</label>

	<h3>Question 2</h3>

	<label>
	<input type="radio" name="answers[2]" value="A">
	Answer A
	</label>

	<label>
	<input type="radio" name="answers[2]" value="B" data-correct>
	Answer B
	</label>

	<label>
	<input type="radio" name="answers[2]" value="C">
	Answer C
	</label>

	<input type="submit">
	<form>

	<script src="jquery.js" type="text/javascript"></script>
	<script src="jquery.simpleQuiz.js" type="text/javascript"></script>

	<script type="text/javascript">
	$(document).ready(function() {
	$('.simple-quiz').simpleQuiz();
	});
	</script>
	</body>
	</html>
	$.fn.every = function(callback) {
	var numElements = this.length;
	return this.filter(callback).length == numElements;
	};

	$.fn.simpleQuiz = function(options) {
	if(!this.length) { return; };

	this.each(function() {
	var form = $(this);
	var submitButton = form.find(':submit');
	var questions = form.find('.question');
	var choices = form.find(':radio');

	var init = function() {
	choices.on('change', answerChanged);
	form.on('submit', answersSubmitted);

	answerChanged();
	};

	var answersSubmitted = function(event) {
	if(!hasPassed()) {
	event.preventDefault();
	alert('Please try again.');
	}
	};

	var score = function() {
	return form.find(':checked[data-correct]').length;
	};

	var hasPassed = function() {
	return score() == questions.length;
	};

	var hasCheckedElement = function() {
	return $(this).has(':checked').length;
	};

	var allQuestionsAnswered = function() {
	return questions.every(hasCheckedElement);
	};

	var answerChanged = function() {
	if(allQuestionsAnswered()) {
	submitButton.removeAttr('disabled');
	} else {
	submitButton.attr('disabled', 'disabled');
	}
	};

	init();
	});

	};