HTML animationcancel DOM Event: Reference and Examples

When someone interacts with a webpage, the browser sends events to the relevant JavaScript code. The animationcancel event happens when a CSS animation ends unexpectedly without reaching its normal finish.

When animationcancel happens

A CSS animation ends unexpectedly without reaching its normal finish.

You can listen for it using addEventListener(). That keeps event handling separate from HTML attributes such as onclick and works well with modern code organization.

A small working example

<style>
    @keyframes demoPulse { from { opacity: 1; } to { opacity: .4; } }
    .animated-box { animation: demoPulse 2s 2 alternate; }
</style>
<div id="demo-target" class="animated-box">Animate this box with CSS</div>
<p id="event-status" role="status">Waiting for animationcancel...</p>
<script>
    const eventTarget = document.getElementById("demo-target");
    const eventStatus = document.getElementById("event-status");

    if (eventTarget) {
        eventTarget.addEventListener("animationcancel", (eventDetails) => {
            eventStatus.textContent = "animationcancel event received";
            console.log(eventDetails.type, eventDetails.target);
        });
    }
</script>

Reading the code

The browser listens for animationcancel on the relevant target. When the event occurs, the callback receives eventDetails, updates the status message and logs the event name and target in Developer Tools.

Remove the animation class before it finishes; CSS animation rules must exist.

The CSS rule above makes the animation or transition possible. Without a real animated property, a listener alone cannot make these events fire.

Try it in your browser

Open the page, show the Console panel, and follow this test: Remove the animation class before it finishes; CSS animation rules must exist. Then change one thing in the example and observe whether the event still fires.

Common Beginner Mistakes

• Expecting animationcancel to fire without its required user action or browser condition.
• Remove the animation class before it finishes; CSS animation rules must exist.
• Adding repeated event listeners without considering cleanup or unwanted side effects.

Key Takeaways

• animationcancel reports a CSS animation ends unexpectedly without reaching its normal finish.
• addEventListener("animationcancel", ...) listens for the event on the appropriate target.
• Remove the animation class before it finishes; CSS animation rules must exist.