JavaScript setTimeout

Written by Swapnil RajaPublished 24 Aug 2026

setTimeout runs a function once after a delay.

The delay is in milliseconds, so 1000 is one second.

It returns an id you can use to cancel it.

Example

javascript

setTimeout(function () {
  console.log("done");
}, 10);

The message appears after ten milliseconds.

What is setTimeout?

setTimeout schedules a function to run once, later.

The delay is a minimum, not a promise - the function runs when the thread is free.

clearTimeout cancels it before it fires.

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Complete Example

html

<!DOCTYPE html>
<html>
<head>
  <title>JavaScript setTimeout</title>
</head>
<body>

  <h1>setTimeout</h1>

  <p id="out">Waiting...</p>
  <button id="cancel">Cancel</button>

  <script>
    const out = document.getElementById("out");

    const id = setTimeout(function () {
      out.textContent = "Two seconds have passed";
    }, 2000);

    document.getElementById("cancel").addEventListener("click", function () {
      clearTimeout(id);
      out.textContent = "Cancelled";
    });
  </script>

</body>
</html>

JavaScript setTimeout

Example

What is setTimeout?

Syntax

Cancelling a Timer

Example

Passing Arguments

Example

A Delay of Zero Still Waits

Example

The Brackets Mistake

Example

Timers Are Not Exact

Example

Complete Example

Try It Yourself

Important Points

Conclusion