Auto-play the Chrome Dino Game with JavaScript

Want the dino to play itself? Here’s a bot you can drop into the Chrome DevTools Console — no installs, no extensions, just JavaScript.

🤖 The Full Auto-play Script

Paste this into the Chrome DevTools Console (press F12 → Console tab) while the Dino game is running, then press Enter. The dino will start dodging obstacles automatically.

function dispatchKey(type, key) {
    document.dispatchEvent(new KeyboardEvent(type, {keyCode: key}));
}
const autoPlay = setInterval(function () {
    const KEY_CODE_SPACE_BAR = 32
    const KEY_CODE_ARROW_DOWN = 40
    const CANVAS_HEIGHT = Runner.getInstance().dimensions.height
    const DINO_HEIGHT = Runner.getInstance().tRex.config.height

    const obstacle = Runner.getInstance().horizon.obstacles[0]
    const speed = Runner.getInstance().currentSpeed

    if (obstacle) {
        const w = obstacle.width
        const x = obstacle.xPos // measured from left of canvas
        const y = obstacle.yPos // measured from top of canvas
        const yFromBottom = CANVAS_HEIGHT - y - obstacle.typeConfig.height
        const isObstacleNearby = x < 25 * speed - w / 2

        if (isObstacleNearby) {
            if (yFromBottom > DINO_HEIGHT) {
                // Pterodactyl going from above, do nothing
            } else if (y > CANVAS_HEIGHT / 2) {
                // Jump
                dispatchKey("keyup", KEY_CODE_ARROW_DOWN)
                dispatchKey("keydown", KEY_CODE_SPACE_BAR)
            } else {
                // Duck
                dispatchKey("keydown", KEY_CODE_ARROW_DOWN)
            }
        }
    }
}, Runner.getInstance().msPerFrame);

That’s it — copy, paste, run, and watch your dino become a pro! 🦕

If you want to understand how each piece works, read on.

🗝️ Simulating Keyboard Input

function dispatchKey(type, key) {
    document.dispatchEvent(new KeyboardEvent(type, {keyCode: key}));
}

The Dino game listens for real keyboard events (keydown / keyup) on the document. Instead of physically pressing a key, we fire a synthetic KeyboardEvent that looks exactly like the real thing to the game.

type is "keydown" or "keyup".
key is the numeric key code — 32 for Space Bar (jump) and 40 for Arrow Down (duck).

By dispatching these events programmatically, the bot can trigger jumps and ducks at precisely the right moment.

⏱️ The Game Loop

const autoPlay = setInterval(function () {
    // ... check and react to obstacles
}, Runner.getInstance().msPerFrame);

setInterval runs our callback repeatedly at the interval we specify. Instead of a hard-coded value like 16 ms, we use Runner.getInstance().msPerFrame — the exact frame duration the game itself uses.

This means the bot checks for obstacles once per frame, keeping it perfectly in sync with the game’s own rendering loop and avoiding both over-checking and under-checking.

We store the return value in autoPlay so we can stop the bot later — see Stopping Auto-play below.

🚧 Finding the Nearest Obstacle

const obstacle = Runner.getInstance().horizon.obstacles[0]

The game stores all active obstacles in Runner.getInstance().horizon.obstacles, an array ordered from left to right. Index 0 is always the closest obstacle ahead of the dino — the one we need to react to first.

If the array is empty (no obstacles on screen yet), obstacle will be undefined and the whole if (obstacle) block is skipped safely.

📏 Deciding When to React

const w = obstacle.width
const x = obstacle.xPos // measured from left of canvas
const isObstacleNearby = x < 25 * speed - w / 2

We don’t want to jump the moment an obstacle appears — that would be far too early. Instead, we calculate a reaction threshold based on the current game speed:

speed is Runner.getInstance().currentSpeed — it increases as the game progresses.
The threshold 25 * speed - w / 2 grows with speed, so the bot reacts earlier when things are moving faster (giving it enough time to complete the jump or duck before the obstacle arrives).
Subtracting half the obstacle’s width (w / 2) centres the threshold on the obstacle rather than its left edge.

The bot only acts when x (the obstacle’s left edge, measured from the left of the canvas) drops below this threshold.

🦅 Jump, Duck, or Do Nothing?

const yFromBottom = CANVAS_HEIGHT - y - obstacle.typeConfig.height
const DINO_HEIGHT = Runner.getInstance().tRex.config.height

if (yFromBottom > DINO_HEIGHT) {
    // Pterodactyl going from above, do nothing
} else if (y > CANVAS_HEIGHT / 2) {
    // Jump
    dispatchKey("keyup", KEY_CODE_ARROW_DOWN)
    dispatchKey("keydown", KEY_CODE_SPACE_BAR)
} else {
    // Duck
    dispatchKey("keydown", KEY_CODE_ARROW_DOWN)
}

Obstacle positions use the top-left corner as origin, so we compute yFromBottom — how far the obstacle’s bottom edge is from the ground. This tells us whether the obstacle is flying high or sitting on the ground.

Three cases:

Pterodactyl flying high (yFromBottom > DINO_HEIGHT): the obstacle is high enough that the dino can run under it standing up. Do nothing.
Ground-level obstacle (y > CANVAS_HEIGHT / 2): the obstacle is in the lower half of the canvas — a cactus or low-flying pterodactyl. Send a keyup Arrow Down first (to cancel any active duck), then keydown Space Bar to jump.
Mid-height obstacle (everything else): the obstacle is hovering at mid-height — a pterodactyl the dino can’t jump over but can duck under. Send keydown Arrow Down to duck.

🛑 Stopping Auto-play

Because we stored the interval ID in autoPlay, stopping the bot is a single line:

clearInterval(autoPlay)

Run this in the Console whenever you want to take back control of the dino.

🏁 Putting It All Together

Every frame the bot:

Looks at the first obstacle in the queue.
Calculates whether it’s close enough to warrant a reaction.
Reads the obstacle’s vertical position to decide: ignore it, jump over it, or duck under it.
Fires the appropriate synthetic keyboard event.

The result is a dino that plays indefinitely, reacting to every cactus and pterodactyl the game throws at it.

This auto-play script is just one of many tricks you can pull off in the Chrome Dino game. Check out Hacking the Chrome Dino Game for god mode, speed tweaks, score manipulation, and more!