The global clearTimeout() method cancels a timeout previously established by calling setTimeout().

If the parameter provided does not identify a previously established action, this method does nothing.

timeoutID

The identifier of the timeout you want to cancel. This ID was returned by the corresponding call to setTimeout().

It's worth noting that the pool of IDs used by setTimeout() and setInterval() are shared, which means you can technically use clearTimeout() and clearInterval() interchangeably. However, for clarity, you should avoid doing so.

None (undefined).

Run the script below in the context of a web page and click on the page once. You'll see a message popping up in a second. If you click the page multiple times in one second, the alert only appears once.

const alarm = {
  remind(aMessage) {
    alert(aMessage);
    this.timeoutID = undefined;
  },

  setup() {
    if (typeof this.timeoutID === "number") {
      this.cancel();
    }

    this.timeoutID = setTimeout(
      (msg) => {
        this.remind(msg);
      },
      1000,
      "Wake up!",
    );
  },

  cancel() {
    clearTimeout(this.timeoutID);
  },
};
window.addEventListener("click", () => alarm.setup());

Passing an invalid ID to clearTimeout() silently does nothing; no exception is thrown.

• setTimeout()
• setInterval()
• clearInterval()
• Window.requestAnimationFrame()