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Quiz App With Javascript

Hey everyone. Welcome to today’s tutorial. In today’s tutorial, we will learn how to create a quiz web app. To build this app, we need HTML, CSS and Javascript.

I would suggest this project for javascript intermediates. If you are looking for other javascript projects to improve your skills you can check out this playlist here. This playlist from my youtube channel consists of projects with difficulty ranging from easy to complex.

You can choose any of these projects and get started. All these projects come along with free downloadable source code.

Video Tutorial:

If you are interested in learning by watching the video tutorial rather than reading this blog post, you should check out the video down below. Also, subscribe to my youtube channel, where I post new tutorials and tips based on web development regularly.

Project Folder Structure:

Before we start coding, let us create the project folder structure. We start by creating a folder called – “Quiz App”. Inside this folder, we have three files – index.html, style.css and script.js. The first file is the HTML document. Next, we have the stylesheet, and finally, we have the script file.

HTML:

We begin with the HTML code. HTML creates the elements necessary to create the structure and layout of our app. First, copy the code below and paste it into your HTML document.

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>MCQ Quiz</title>
    <!-- Google Font -->
    <link
      href="https://fonts.googleapis.com/css2?family=Poppins:wght@400;600&display=swap"
      rel="stylesheet"
    />
    <!-- Stylesheet -->
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <div class="start-screen">
      <button id="start-button">Start</button>
    </div>
    <div id="display-container">
      <div class="header">
        <div class="number-of-count">
          <span class="number-of-question">1 of 3 questions</span>
        </div>
        <div class="timer-div">
          <img src="timer-icon.svg" />
          <span class="time-left">10s</span>
        </div>
      </div>
      <div id="container">
        <!-- questions and options will be displayed here -->
      </div>
      <button id="next-button">Next</button>
    </div>
    <div class="score-container hide">
      <div id="user-score">Demo Score</div>
      <button id="restart">Restart</button>
    </div>
    <!-- Script -->
    <script src="script.js"></script>
  </body>
</html>

CSS:

Next, we style the app using CSS. For this copy, the code provided to you below and paste it into your stylesheet.

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  background-color: #0a69ed;
}
.start-screen,
.score-container {
  position: absolute;
  top: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
button {
  border: none;
  outline: none;
  cursor: pointer;
}
#start-button,
#restart {
  font-size: 1.3em;
  padding: 0.5em 1.8em;
  border-radius: 0.2em;
}
#restart {
  margin-top: 0.9em;
}
#display-container {
  background-color: #ffffff;
  padding: 3.1em 1.8em;
  width: 80%;
  max-width: 37.5em;
  margin: 0 auto;
  position: absolute;
  transform: translate(-50%, -50%);
  top: 50%;
  left: 50%;
  border-radius: 0.6em;
}
.header {
  margin-bottom: 1.8em;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 0.6em;
  border-bottom: 0.1em solid #c0bfd2;
}
.timer-div {
  background-color: #e1f5fe;
  width: 7.5em;
  border-radius: 1.8em;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.7em 1.8em;
}
.question {
  margin-bottom: 1.25em;
  font-weight: 600;
}
.option-div {
  font-size: 0.9em;
  width: 100%;
  padding: 1em;
  margin: 0.3em 0;
  text-align: left;
  outline: none;
  background: transparent;
  border: 1px solid #c0bfd2;
  border-radius: 0.3em;
}
.option-div:disabled {
  color: #000000;
  cursor: not-allowed;
}
#next-button {
  font-size: 1em;
  margin-top: 1.5em;
  background-color: #0a69ed;
  color: #ffffff;
  padding: 0.7em 1.8em;
  border-radius: 0.3em;
  float: right;
}
.hide {
  display: none;
}
.incorrect {
  background-color: #ffdde0;
  color: #d32f2f;
  border-color: #d32f2f;
}
.correct {
  background-color: #e7f6d5;
  color: #689f38;
  border-color: #689f38;
}
#user-score {
  font-size: 1.5em;
  color: #ffffff;
}

Javascript:

Finally, we add functionality to our quiz app using Javascript. Now copy the code below and paste it into your script file. We build the quiz app in 8 easy steps:
1: Create Initial References
2: Create Questions & Options Array
3: Implement quizCreator()
4: Function To Display Quiz
5: Show Start Screen On Window Load
6: Create Timer
7: Function To Check If Selected Option Is Correct
8: Implement Functionality For Next Button

//References
let timeLeft = document.querySelector(".time-left");
let quizContainer = document.getElementById("container");
let nextBtn = document.getElementById("next-button");
let countOfQuestion = document.querySelector(".number-of-question");
let displayContainer = document.getElementById("display-container");
let scoreContainer = document.querySelector(".score-container");
let restart = document.getElementById("restart");
let userScore = document.getElementById("user-score");
let startScreen = document.querySelector(".start-screen");
let startButton = document.getElementById("start-button");
let questionCount;
let scoreCount = 0;
let count = 11;
let countdown;

//Questions and Options array

const quizArray = [
  {
    id: "0",
    question: "Which is the most widely spoken language in the world?",
    options: ["Spanish", "Mandarin", "English", "German"],
    correct: "Mandarin",
  },
  {
    id: "1",
    question: "Which is the only continent in the world without a desert?",
    options: ["North America", "Asia", "Africa", "Europe"],
    correct: "Europe",
  },
  {
    id: "2",
    question: "Who invented Computer?",
    options: ["Charles Babbage", "Henry Luce", "Henry Babbage", "Charles Luce"],
    correct: "Charles Babbage",
  },
];

//Restart Quiz
restart.addEventListener("click", () => {
  initial();
  displayContainer.classList.remove("hide");
  scoreContainer.classList.add("hide");
});

//Next Button
nextBtn.addEventListener(
  "click",
  (displayNext = () => {
    //increment questionCount
    questionCount += 1;
    //if last question
    if (questionCount == quizArray.length) {
      //hide question container and display score
      displayContainer.classList.add("hide");
      scoreContainer.classList.remove("hide");
      //user score
      userScore.innerHTML =
        "Your score is " + scoreCount + " out of " + questionCount;
    } else {
      //display questionCount
      countOfQuestion.innerHTML =
        questionCount + 1 + " of " + quizArray.length + " Question";
      //display quiz
      quizDisplay(questionCount);
      count = 11;
      clearInterval(countdown);
      timerDisplay();
    }
  })
);

//Timer
const timerDisplay = () => {
  countdown = setInterval(() => {
    count--;
    timeLeft.innerHTML = `${count}s`;
    if (count == 0) {
      clearInterval(countdown);
      displayNext();
    }
  }, 1000);
};

//Display quiz
const quizDisplay = (questionCount) => {
  let quizCards = document.querySelectorAll(".container-mid");
  //Hide other cards
  quizCards.forEach((card) => {
    card.classList.add("hide");
  });
  //display current question card
  quizCards[questionCount].classList.remove("hide");
};

//Quiz Creation
function quizCreator() {
  //randomly sort questions
  quizArray.sort(() => Math.random() - 0.5);
  //generate quiz
  for (let i of quizArray) {
    //randomly sort options
    i.options.sort(() => Math.random() - 0.5);
    //quiz card creation
    let div = document.createElement("div");
    div.classList.add("container-mid", "hide");
    //question number
    countOfQuestion.innerHTML = 1 + " of " + quizArray.length + " Question";
    //question
    let question_DIV = document.createElement("p");
    question_DIV.classList.add("question");
    question_DIV.innerHTML = i.question;
    div.appendChild(question_DIV);
    //options
    div.innerHTML += `
    <button class="option-div" onclick="checker(this)">${i.options[0]}</button>
     <button class="option-div" onclick="checker(this)">${i.options[1]}</button>
      <button class="option-div" onclick="checker(this)">${i.options[2]}</button>
       <button class="option-div" onclick="checker(this)">${i.options[3]}</button>
    `;
    quizContainer.appendChild(div);
  }
}

//Checker Function to check if option is correct or not
function checker(userOption) {
  let userSolution = userOption.innerText;
  let question =
    document.getElementsByClassName("container-mid")[questionCount];
  let options = question.querySelectorAll(".option-div");

  //if user clicked answer == correct option stored in object
  if (userSolution === quizArray[questionCount].correct) {
    userOption.classList.add("correct");
    scoreCount++;
  } else {
    userOption.classList.add("incorrect");
    //For marking the correct option
    options.forEach((element) => {
      if (element.innerText == quizArray[questionCount].correct) {
        element.classList.add("correct");
      }
    });
  }

  //clear interval(stop timer)
  clearInterval(countdown);
  //disable all options
  options.forEach((element) => {
    element.disabled = true;
  });
}

//initial setup
function initial() {
  quizContainer.innerHTML = "";
  questionCount = 0;
  scoreCount = 0;
  count = 11;
  clearInterval(countdown);
  timerDisplay();
  quizCreator();
  quizDisplay(questionCount);
}

//when user click on start button
startButton.addEventListener("click", () => {
  startScreen.classList.add("hide");
  displayContainer.classList.remove("hide");
  initial();
});

//hide quiz and display start screen
window.onload = () => {
  startScreen.classList.remove("hide");
  displayContainer.classList.add("hide");
};

That’s it for this tutorial. Our quiz app is now ready. If you face any issues while creating this project, you can download the source code by clicking on the download button below. Also, I would love to hear from you guys, so forget to drop your queries, suggestions and feedback below.

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