CookieStore: change event

Baseline 2025

Newly available

Since June 2025, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

A change event is fired at a CookieStore object when a change is made to any cookie.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("change", (event) => { })

onchange = (event) => { }

To be informed when a cookie has changed, you can add a handler to the cookieStore instance using addEventListener(), like this:

cookieStore.addEventListener("change", (event) => {
  console.log("1 change event");
});

Alternatively, you can use the onchange event handler property to establish a handler for the change event:

cookieStore.onchange = (event) => {
  console.log("1 change event");
};

Specification
Cookie Store API # intro-monitor
Cookie Store API # dom-cookiestore-onchange