displayquiz.js

function showResults(questions, quizContainer, resultsContainer){

	// gather answer containers from our quiz
	var answerContainers = quizContainer.querySelectorAll('.answers');

	// keep track of user's answers
	var userAnswer = '';
	var numCorrect = 0;

	// for each question...
	for(var i=0; i<questions.length; i++){

		// find selected answer
		userAnswer = (answerContainers[i].querySelector('input[name=question'+i+']:checked')||{}).value;

		// if answer is correct
		if(userAnswer===questions[i].correctAnswer){
			// add to the number of correct answers
			numCorrect++;

			// color the answers green
			answerContainers[i].style.color = 'lightgreen';
		}
		// if answer is wrong or blank
		else{
			// color the answers red
			answerContainers[i].style.color = 'red';
		}
	}

	// show number of correct answers out of total
	resultsContainer.innerHTML = numCorrect + ' out of ' + questions.length;
}