HTML hashchange DOM Event: Reference and Examples

When someone interacts with a webpage, the browser sends events to the relevant JavaScript code. The hashchange event happens when the fragment identifier in the current URL changes.

When hashchange happens

The fragment identifier in the current URL changes.

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

<p>Try the relevant browser action described below.</p>
<p id="event-status" role="status">Waiting for hashchange...</p>
<script>
    const eventTarget = window;
    const eventStatus = document.getElementById("event-status");

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

Reading the code

The browser listens for hashchange 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.

Activate an in-page fragment link such as #details.

The oldURL and newURL values identify the change; pushState does not cause hashchange.

Some events need a specific browser condition, another tab or window, or a Web Component to reproduce. Read the trigger steps carefully before deciding that an event handler is not working.

Try it in your browser

Open the page, show the Console panel, and follow this test: Activate an in-page fragment link such as #details. Then change one thing in the example and observe whether the event still fires.

Common Beginner Mistakes

• Expecting hashchange to fire without its required user action or browser condition.
• Activate an in-page fragment link such as #details.
• Adding repeated event listeners without considering cleanup or unwanted side effects.

Key Takeaways

• hashchange reports the fragment identifier in the current URL changes.
• addEventListener("hashchange", ...) listens for the event on the appropriate target.
• Activate an in-page fragment link such as #details.