window.clearTimeout() cancels a one-shot timer created by setTimeout() (MDN). Pass the ID from setTimeout. Unknown IDs are ignored.
Pass the required arguments shown below. Check return values and browser support before you rely on the result.
Call window.clearTimeout. Start with this line.
clearTimeout(timeoutID)| Call | What it does |
|---|---|
clearTimeout(timeoutID) | Primary signature. |
window.clearTimeout(...) | Call with the arguments your case needs. |
Built into the browser. Call window.clearTimeout(...) (or the global clearTimeout(...)) — no import required.
clearTimeout(timeoutID)| Parameter | Description |
|---|---|
| timeoutID | Required. ID returned by setTimeout() |
| Return Value | Description |
|---|---|
| * | Always undefined |
Schedule a timeout, then clear it immediately so it never fires.
const id = setTimeout(function () {
console.log("hello");
}, 1000);
clearTimeout(id);
console.log("cancelled"); // cancelled (no "hello")setTimeout.clearTimeout."hello" never logs.clearTimeout itself returns undefined.Start a delayed message; cancel it before one second passes.
// Imagine buttons: Start / Cancel and <pre id="out">
let id = null;
function start() {
clearTimeout(id);
document.getElementById("out").textContent = "Waiting 1s...";
id = setTimeout(function () {
document.getElementById("out").textContent = "Done!";
id = null;
}, 1000);
}
function cancel() {
clearTimeout(id);
id = null;
document.getElementById("out").textContent = "Cancelled";
}clearTimeout(id) before it fires.id = null when done or cancelled.Each new call clears the previous timeout — only the last pause fires.
let id = null;
function onType(value) {
clearTimeout(id);
id = setTimeout(function () {
console.log("search:", value);
}, 300);
}
onType("c");
onType("co");
onType("cod");
// only "search: cod" logs (after 300ms quiet)setTimeout with the latest value.Calling clearTimeout again with the same ID is safe.
const id = setTimeout(function () {}, 1000);
clearTimeout(id);
clearTimeout(id); // no error
console.log("ok");id = null in real apps for clarity.A fake ID does nothing — and does not throw.
clearTimeout(999999);
console.log("still ok");setTimeout.setTimeout in practice.Window.clearTimeout() is marked Baseline Widely available on MDN (since July 2015). Browser Window API — also available in workers.
Cancel one-shot timers across modern browsers.
Bottom line: Safe everywhere you use setTimeout. Always clear pending timeouts that should not run.
Close the current browsing context when the browser allows it.
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