quiz app in javascript code example

Example 1: build a trivia and answer javascript

// code by webdevtrick (https://webdevtrick.com)
function Quiz(questions) {
    this.score = 0;
    this.questions = questions;
    this.questionIndex = 0;
}
 
Quiz.prototype.getQuestionIndex = function() {
    return this.questions[this.questionIndex];
}
 
Quiz.prototype.guess = function(answer) {
    if(this.getQuestionIndex().isCorrectAnswer(answer)) {
        this.score++;
    }
 
    this.questionIndex++;
}
 
Quiz.prototype.isEnded = function() {
    return this.questionIndex === this.questions.length;
}
 
 
function Question(text, choices, answer) {
    this.text = text;
    this.choices = choices;
    this.answer = answer;
}
 
Question.prototype.isCorrectAnswer = function(choice) {
    return this.answer === choice;
}
 
 
function populate() {
    if(quiz.isEnded()) {
        showScores();
    }
    else {
        // show question
        var element = document.getElementById("question");
        element.innerHTML = quiz.getQuestionIndex().text;
 
        // show options
        var choices = quiz.getQuestionIndex().choices;
        for(var i = 0; i < choices.length; i++) {
            var element = document.getElementById("choice" + i);
            element.innerHTML = choices[i];
            guess("btn" + i, choices[i]);
        }
 
        showProgress();
    }
};
 
function guess(id, guess) {
    var button = document.getElementById(id);
    button.onclick = function() {
        quiz.guess(guess);
        populate();
    }
};
 
 
function showProgress() {
    var currentQuestionNumber = quiz.questionIndex + 1;
    var element = document.getElementById("progress");
    element.innerHTML = "Question " + currentQuestionNumber + " of " + quiz.questions.length;
};
 
function showScores() {
    var gameOverHTML = "<h1>Result</h1>";
    gameOverHTML += "<h2 id='score'> Your scores: " + quiz.score + "</h2>";
    var element = document.getElementById("quiz");
    element.innerHTML = gameOverHTML;
};
 
// create questions here
var questions = [
    new Question("Hyper Text Markup Language Stand For?", ["JavaScript", "XHTML","CSS", "HTML"], "HTML"),
    new Question("Which language is used for styling web pages?", ["HTML", "JQuery", "CSS", "XML"], "CSS"),
    new Question("Which is not a JavaScript Framework?", ["Python Script", "JQuery","Django", "NodeJS"], "Django"),
    new Question("Which is used for Connect To Database?", ["PHP", "HTML", "JS", "All"], "PHP"),
    new Question("Webdevtrick.com is about..", ["Web Design", "Graphic Design", "SEO & Development", "All"], "All")
];
 
// create quiz
var quiz = new Quiz(questions);
 
// display quiz
populate();

Example 2: build a trivia and answer javascript

/** code by webdevtrick (https://webdevtrick.com) **/
body {
    background-color: #413D3D;
}
 
.grid {
    width: 600px;
    height: 500px;
    margin: 0 auto;
    background-color: #fff;
    padding: 10px 50px 50px 50px;
    border: 2px solid #cbcbcb;
    
}
 
.grid h1 {
    font-family: "sans-serif";
    background-color: #01BBFF;
    font-size: 60px;
    text-align: center;
    color: #ffffff;
    padding: 2px 0px;
    
}
 
#score {
    color: #01BBFF;
    text-align: center;
    font-size: 30px;
}
 
.grid #question {
    font-family: "monospace";
    font-size: 30px;
    color: #01BBFF;
}
 
.buttons {
    margin-top: 30px;
}
 
#btn0, #btn1, #btn2, #btn3 {
    background-color: #01BBFF;
    width: 250px;
    font-size: 20px;
    color: #fff;
    border: 1px solid #1D3C6A;
    margin: 10px 40px 10px 0px;
    padding: 10px 10px;
}
 
#btn0:hover, #btn1:hover, #btn2:hover, #btn3:hover {
    cursor: pointer;
    background-color: #01BBFF;
}
 
#btn0:focus, #btn1:focus, #btn2:focus, #btn3:focus {
    outline: 0;
}
 
#progress {
    color: #2b2b2b;
    font-size: 18px;
}