HTML animationend DOM Event: Reference and Examples

When someone interacts with a webpage, the browser sends events to the relevant JavaScript code. The animationend event happens when a CSS animation reaches its end.

When animationend happens

A CSS animation reaches its end.

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 animationend...</p>
<script>
    const eventTarget = document.getElementById("demo-target");
    const eventStatus = document.getElementById("event-status");

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

Reading the code

The browser listens for animationend 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.

Play a CSS animation and wait until it finishes normally.

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: Play a CSS animation and wait until it finishes normally. Then change one thing in the example and observe whether the event still fires.

Common Beginner Mistakes

• Expecting animationend to fire without its required user action or browser condition.
• Play a CSS animation and wait until it finishes normally.
• Adding repeated event listeners without considering cleanup or unwanted side effects.

Key Takeaways

• animationend reports a CSS animation reaches its end.
• addEventListener("animationend", ...) listens for the event on the appropriate target.
• Play a CSS animation and wait until it finishes normally.