Building a web-based JavaScript game: Step-by-Step Guide

So you’re ready to start building your game. This guide works in a slightly different way so far. You are going to build the game as you work through the assignment. Follow the step-by-step instructions and copy the code, and you’ll have the game ready in no time.

Building a Web-based JavaScript Game

1) Create an HTML file (Building a web-based JavaScript game)

Start by creating a new HTML file named securitygame.html and use the following template:

<!DOCTYPE html>
<html>
<head>
    <title>Security Game</title>
</head>
<body>
</body>
</html>

2) Build the game board

Add a <div> to the <body> to serve as the game board and style it with CSS in the <head>:

<body>
<div id="board"></div>
</body>

<style>
#board {
    border: 1px solid black;
    background-color: gray;
    height: 350px;
    width: 650px;
}
</style>

3) Add a button

Insert a button above the <div> to start the game:

<input type="button" value="Play" onclick="startGame();"/>

Then, define the startGame function within a <script> tag:

<script>
function startGame() {
    // Game initialization code goes here
}
</script>

4) Create a JavaScript timer

Use setTimeout to create a timer for game events:

setTimeout(gameTimer, 1000);

5) Create a game loop

Implement a game loop to continuously run game logic:

function gameLoop() {
    // Game logic goes here
    setTimeout(gameLoop, 3000);
}

6) Add the guests and thief to the game board

Modify the game board to include characters, distinguishing the thief:

<div id="board">
    <div>Guest</div>
    <div>Guest</div>
    // More guests here
    <div>Thief</div>
</div>

7) Use the game loop to stop the game

Adjust the game loop to stop after a certain condition is met, such as a timer expiring or a score limit reached.

8) Use CSS to show and hide the characters

Control the visibility of characters with CSS classes .hidden and .visible applied dynamically with JavaScript.

Final Steps – Building a web-based JavaScript game

Follow the above steps to build the game’s functionality, focusing on JavaScript logic and interaction, CSS for styling, and HTML for structure. Refine your game by adding more features, improving the design, and testing for bugs.

9) Animate the characters

To animate the characters, use JavaScript to toggle the .hidden and .visible classes on each game loop iteration.

10) Apply CSS using JavaScript

Adjust the appearance of your characters dynamically with JavaScript by adding or removing CSS classes based on game state:

function flashCharacters() {
    var characters = document.querySelectorAll('.character');
    characters.forEach(function(character) {
        character.classList.toggle('hidden');
    });
}

11) Simplify the conditional statements

Use the conditional (ternary) operator to simplify your JavaScript logic for cleaner code:

var classToSet = peopleVisible ? "visible" : "hidden";

12) Create the thief

Randomly select one character to be the thief in each game loop iteration:

function assignThief() {
    var characters = document.querySelectorAll('.character');
    var thiefIndex = Math.floor(Math.random() * characters.length);
    characters[thiefIndex].classList.add('thief');
}

13) Create a score

Implement a scoring system by adding event listeners to characters for player interaction:

function setupCharacters() {
    var characters = document.querySelectorAll('.character');
    characters.forEach(function(character) {
        character.addEventListener('click', function() {
            if (this.classList.contains('thief')) {
                gameScore++;
            } else {
                gameScore--;
            }
        });
    });
}

14) Simplify the code

Refactor your game’s JavaScript to improve readability and efficiency. Combine similar functions where possible, and remove redundant code.

15) Designing the game with CSS

Enhance your game’s visual appeal with CSS. Consider adding backgrounds, animations, and transitions for a polished look:

.character {
    /* Character styling */
}
.character.thief {
    /* Special styling for the thief */
}

16) Use images for the characters

Replace character divs with images for a more engaging game experience:

.character {
    background-image: url('path/to/guest-image.png');
}
.character.thief {
    background-image: url('path/to/thief-image.png');
}

17) Change the game board

Customize the game board with your own design to match the theme of your game:

#board {
    background-image: url('path/to/board-background.png');
}

18) Make the game harder

Adjust the game’s difficulty by reducing the visibility time of characters or increasing the speed of the game loop:

setTimeout(gameLoop, peopleVisible ? 500 : 2500);

With these steps, you will have built a basic but functional web-based JavaScript game. Continue to refine and add features to your game to improve the player experience.

19) Add sound effects

Enhance your game’s immersion with sound effects for actions like selecting the thief or making a wrong guess:

function playSound(effect) {
    var audio = new Audio('path/to/' + effect + '.mp3');
    audio.play();
}

20) Implement levels and challenges

Introduce levels with increasing difficulty and unique challenges to keep players engaged:

function nextLevel() {
    currentLevel++;
    // Increase speed or change game dynamics
}

21) Add a timer for each round

Integrate a countdown timer for each game round, adding pressure and excitement for the player:

function startTimer(duration) {
    var timer = duration, minutes, seconds;
    setInterval(function () {
        minutes = parseInt(timer / 60, 10);
        seconds = parseInt(timer % 60, 10);

        minutes = minutes < 10 ? "0" + minutes : minutes;
        seconds = seconds < 10 ? "0" + seconds : seconds;

        document.querySelector('#time').textContent = minutes + ":" + seconds;

        if (--timer < 0) {
            timer = duration;
            // Handle time up
        }
    }, 1000);
}

22) Create a high score board

Track and display high scores using local storage to motivate players to improve:

function updateHighScores(score) {
    var highScores = JSON.parse(localStorage.getItem('highScores') || '[]');
    highScores.push(score);
    highScores.sort(function(a, b) { return b - a; });
    highScores = highScores.slice(0, 5); // Keep top 5 scores
    localStorage.setItem('highScores', JSON.stringify(highScores));
    
    // Update scoreboard display
}

23) Mobile responsiveness

Ensure your game is playable on various devices by making it responsive. Adjust sizes, controls, and layouts as necessary:

@media (max-width: 768px) {
    /* Adjust styles for smaller screens */
}

24) Testing and debugging

Thoroughly test your game on different browsers and devices. Use debugging tools to identify and fix any issues:

Consider using browser developer tools and logging to track down bugs.

25) Gather feedback and iterate

After launching your game, gather feedback from players. Use insights to make improvements, add features, and refine gameplay:

Consider creating forums, surveys, or social media polls to engage with your audience and collect their opinions.

Conclusion – Building a web-based JavaScript game

Building a web-based JavaScript game involves a mix of creativity, coding skills, and attention to detail. From the basics of setting up your game board to implementing advanced features like levels and sound effects, each step brings its own challenges and rewards. Remember to test extensively, listen to your players, and always look for ways to enhance the gaming experience.

Happy coding, and enjoy bringing your game ideas to life!


Here is how my game looks like with my images.

To play this web-based JavaScript game, follow these simple steps. The objective is to find and click on the “thief” among several characters (the guests) that appear on the game board. Here’s how it works:

  1. Starting the Game: Press the “Play” button on the screen to begin. When you click “Play,” the game board will be initialized, and the game loop starts.
  2. Gameplay:
    • The game consists of several rounds, each lasting a few seconds.
    • During each round, a number of characters will appear on the game board. One of these characters is marked as the “thief,” and the rest are “guests.”
    • The characters may only be visible for a short period (as specified in the game loop), making it a challenge to spot the thief.
  3. Objective:
    • Your task is to quickly identify and click on the thief. Each round presents a new arrangement of characters with one of them being the thief.
    • Be fast! You need to click on the thief before the characters disappear to proceed to the next round.
  4. Scoring:
    • Each time you correctly click on the thief, you gain a point.
    • If you click on a guest instead of the thief, you lose a point.
    • The game keeps track of your score and displays it on the screen as you play.
  5. Winning and Losing:
    • The game continues for a set number of rounds (loops).
    • Your goal is to score as many points as possible by accurately identifying the thief in each round.
    • At the end of the game, your final score is displayed. A higher score indicates better performance.
  6. End of the Game:
    • Once the game has gone through all the rounds, an alert will pop up to inform you that the game is over and display your final score.
    • You can then start a new game by pressing the “Play” button again.

This game tests your observation skills and reaction time. To succeed, stay focused on the game board and try to quickly distinguish the thief from the guests. Each playthrough can be a bit different due to the random placement of the thief, providing a fresh challenge every time. Enjoy the game and aim for a high score!

Security Game
Score: 0

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About the Author: Bernard Aybout

In the land of bytes and bits, a father of three sits,With a heart for tech and coding kits, in IT he never quits.At Magna's door, he took his stance, in Canada's wide expanse,At Karmax Heavy Stamping - Cosma's dance, he gave his career a chance.With a passion deep for teaching code, to the young minds he showed,The path where digital seeds are sowed, in critical thinking mode.But alas, not all was bright and fair, at Magna's lair, oh despair,Harassment, intimidation, a chilling air, made the workplace hard to bear.Management's maze and morale's dip, made our hero's spirit flip,In a demoralizing grip, his well-being began to slip. So he bid adieu to Magna's scene, from the division not so serene,Yet in tech, his interest keen, continues to inspire and convene.