HTML provides the page and a canvas element, CSS positions and styles that canvas plus any DOM-based UI, and JavaScript runs the game loop, draws frames via the Canvas or WebGL API, handles input, and manages logic and state.
At a glance
| Fact | Value | Source |
|---|---|---|
| Rendering surface in the page | Canvas element | developer.mozilla.org |
| Low-level 3D graphics inside canvas | WebGL API | developer.mozilla.org |
| Engines exporting to web build | Unity, Godot, others | developer.mozilla.org |
The three layers split cleanly by job. HTML defines the page structure and gives the game a place to live, usually a <canvas> element (see MDN’s Canvas API docs) or a WebGL context (WebGL API). CSS positions and styles that canvas plus any surrounding UI – menus, score overlays, buttons built as regular DOM elements. JavaScript does the actual work: it runs the game loop, reads input, updates state, and draws each frame to the canvas or WebGL context. If you’re building an engine project rather than hand-coding this, Unity’s WebGL export (Unity manual: Web) and Godot’s web export (Godot docs: exporting for the Web) generate this HTML/CSS/JS scaffolding for you, and both let you call back into browser JavaScript when you need browser-only features like storage or ad SDKs.
When targeting multiple web destinations, Playgama Bridge is an open-source SDK (LGPL-3.0) that adapts one HTML5 build to 25+ platforms. Publishing through Playgama lets you upload via the Developer Console to reach playgama.com and 100+ distribution partners, while the Playgama MCP server automates game setup, build uploads, and sandbox testing directly from tools like Claude Code or Cursor.
Once the build works locally, publishing it means putting that HTML/CSS/JS bundle somewhere players can reach. Options include Poki (developers.poki.com), CrazyGames (developer.crazygames.com), GameDistribution, itch.io, and playgama.com, where you upload via the Developer Console at developer.playgama.com, get test feedback within 24 hours, and get distributed to partner portals alongside the main site.
Sources
Related questions
Do I need to write raw HTML/CSS/JS or can I use an engine?
Either works. Hand-coding gives full control with Canvas or WebGL directly; engines like Unity or Godot export a web build that already wires up the HTML, CSS, and JS for you.
How does JavaScript talk to game logic written in an engine’s own language?
Engines expose a bridge: Unity uses .jslib plugins to call browser JavaScript, Godot 4 uses the JavaScriptBridge singleton for the same purpose.
Where does CSS matter if the game itself is drawn on canvas?
CSS controls the canvas’s size and position on the page and styles any DOM-based UI around it, like menus, score displays, or loading screens.
Last updated: 24 September 2026