JavaScript reference

setInterval

Runs a function again and again at an interval.

Available since: Web API

Syntax

setInterval(callback, delay, ...args)

Parameters

Parameter	Type	Description
callback	Function	The function to run repeatedly.
delay	number	The interval in milliseconds.
...args	any	Optional. Arguments for the function.

Return value

numberThe timer id — for stopping with clearInterval.

Examples

A countdown:

let count = 3;
 
const id = setInterval(() => {
  console.log(count);
  count--;
  if (count === 0) {
    clearInterval(id);
    console.log('Go!');
  }
}, 200);

Output:

3
2
1
Go!

Notes

An interval runs until it is stopped with clearInterval(). Do not forget to stop it, or the function is called forever.

Related recipes

How to run code repeatedly at an interval

In the tutorial

Timers — The setTimeout and setInterval functions in JavaScript: delayed and repeated calls, arguments, cancelling a timer.

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