Ever wondered how browser games work? At AceFun Games, we build all our games using HTML5 Canvas and JavaScript. Here is a beginner-friendly overview of the process.
The Canvas element is a rectangular area on a webpage where you can draw graphics using JavaScript. It provides a pixel-based drawing surface perfect for games, animations, and visualizations.
Every game has a core loop that runs continuously: update game state, check for collisions, handle input, then draw everything to the screen. This loop typically runs 60 times per second for smooth animation.
While game engines like Phaser or Unity exist, we use plain JavaScript for several reasons: smaller file sizes mean faster loading, no dependencies to manage, maximum browser compatibility, and full control over every aspect of the game.
To build your first game, you only need a text editor and a browser. Start with something simple like Pong or Snake to learn the fundamentals. Once you understand the game loop, collision detection, and rendering, you can build almost anything!
All of our games at AceFun Games are built this way — from Snake Classic to Space Dodge, every pixel is drawn with Canvas.
Every HTML5 Canvas game starts with the same basic structure: an HTML file with a canvas element, a CSS file for styling, and a JavaScript file containing the game logic. The canvas element provides a bitmap drawing surface that you control entirely through JavaScript. Unlike DOM-based game frameworks that manipulate HTML elements, Canvas gives you pixel-level control over what appears on screen — making it ideal for games that need smooth animations and precise collision detection.
Here's what the basic setup looks like conceptually: First, you create a canvas element with specific width and height attributes. Then you get the 2D rendering context — this is the object that provides all drawing methods like fillRect(), arc(), drawImage(), and clearRect(). Finally, you create a game loop using requestAnimationFrame that continuously updates game state and redraws the canvas at 60 frames per second.
The game loop is the fundamental pattern that drives every real-time game. It continuously performs three operations in sequence: First, UPDATE — calculate new positions for all game objects based on physics, player input, and AI logic. Second, RENDER — clear the canvas and redraw everything in its new position. Third, REPEAT — schedule the next frame using requestAnimationFrame. This cycle happens 60 times per second (or whatever the monitor's refresh rate is), creating the illusion of smooth, continuous motion from what is actually a rapid sequence of still images.
The key to smooth animation is separating game logic (which should run at a consistent rate regardless of frame rate) from rendering (which should happen as fast as the browser allows). This is why professional game developers use delta-time calculations — measuring the actual time elapsed between frames and using that to scale all movement. This ensures the game runs at the same speed whether the player has a 60Hz monitor or a 144Hz one.
Almost every game needs to detect when objects overlap or touch each other. The simplest form is AABB (Axis-Aligned Bounding Box) collision detection — checking if two rectangles overlap. For circular objects, you calculate the distance between centers and compare it to the sum of their radii. For our games at AceFun Games, we use different collision methods depending on the game: grid-based checking for Snake (is the snake's head on the same grid cell as food or a wall?), AABB for Brick Breaker (is the ball overlapping a brick?), and radius-based for Bubble Pop (did the click land within the bubble's radius?).
Games need to respond to player input — keyboard presses, mouse movements, and touch events. In JavaScript, you attach event listeners to the document or canvas element. For keyboard input, listen for 'keydown' and 'keyup' events. For mouse, listen for 'mousemove', 'mousedown', and 'mouseup'. For touch devices, the equivalent events are 'touchstart', 'touchmove', and 'touchend'. A critical best practice is to store the current input state in variables during event handlers, then read those variables in the game loop — never update game state directly in event handlers, as events can fire at unpredictable rates.
A significant portion of web traffic comes from mobile devices, so your HTML5 games must work on touchscreens. This means implementing touch equivalents for all mouse/keyboard interactions. For our games, we created a reusable mobile support library (mobile.js) that provides: responsive canvas scaling (the canvas automatically resizes to fit the screen width), virtual D-pad controls for games needing directional input, touch-to-click mapping for point-and-click games, and swipe gesture detection for games like Snake. The meta viewport tag is also essential — without it, mobile browsers will zoom out to show the full desktop layout rather than rendering at the correct scale.
Canvas games can become slow if you're not careful about performance. Key optimization strategies include: minimizing canvas state changes (batching operations that use the same fill color), using requestAnimationFrame instead of setInterval (the browser optimizes rAF calls), avoiding unnecessary redraws (only clear and redraw what changed), and reducing garbage collection by reusing objects instead of creating new ones every frame. For our games, these optimizations keep everything running smoothly at 60fps even on budget smartphones.
If you're inspired to build your own games, start with something simple — our Snake tutorial walks through building a complete game in under 150 lines of code. Once you're comfortable with the basics, try recreating some of our other games: Pong is a great second project (introduces AI opponents), Brick Breaker teaches physics (angle calculations), and Memory Cards introduces state management. Every game you build teaches new programming concepts while producing something fun and shareable.