Display "Hello" every second (1000 milliseconds):

setInterval(function () {element.innerHTML += "Hello"}, 1000); Try it Yourself »

Call displayHello every second:

setInterval(displayHello, 1000); Try it Yourself »

More examples below.

Description

The setInterval() method calls a function at specified intervals (in milliseconds).

The setInterval() method continues calling the function until clearInterval() is called, or the window is closed.

1 second = 1000 milliseconds.

To execute the function only once, use the setTimeout() method instead.

To clear an interval, use the id returned from setInterval():

myInterval = setInterval( function , milliseconds );

Then you can to stop the execution by calling clearInterval():

clearInterval(myInterval);

See Also:

The clearInterval() Method

The setTimeout() Method

The clearTimeout() Method

Syntax

setInterval( function, milliseconds, param1, param2, ... )

Parameters

Parameter Description function Required.
The function to execute milliseconds Required.
The execution interval.
If the value is less than 10, 10 is used param1, param2, ... Optional.
Additional parameters to pass to the function
Not supported in IE9 and earlier.

Return Value

Description A numberThe id of the timer.
Use this id with clearInterval() to cancel the timer. {
const date = new Date();
document.getElementById("demo").innerHTML = date.toLocaleTimeString();
} Try it Yourself »

Example

Using clearInterval() to stop the digital watch:

const myInterval = setInterval(myTimer, 1000);

function myTimer() {
const date = new Date();
document.getElementById("demo").innerHTML = date.toLocaleTimeString();
}

function myStopFunction() {
clearInterval(myInterval);
} Try it Yourself »

Example

Using setInterval() and clearInterval() to create a dynamic progress bar:

function move() {
const element = document.getElementById("myBar");
let width = 0;
let id = setInterval(frame, 10);
function frame() {
if (width == 100) {
clearInterval(id);
} else {
width++;
element.style.width = width + '%';
}
}
} Try it Yourself »

Example

Toggle between two background colors once every 500 milliseconds:

const myInterval = setInterval(setColor, 500);

function setColor() {
let x = document.body;
x.style.backgroundColor = x.style.backgroundColor == "yellow" ? "pink" : "yellow";
}

function stopColor() {
clearInterval(myInterval);
} Try it Yourself »

Example

Pass parameters to the function (does not work in IE9 and earlier):

setInterval(myFunc, 2000, "param1", "param2"); Try it Yourself »

However, if you use an anonymous function it works in all browsers:

setInterval(function() {myFunc("param1", "param2")}, 2000); Try it Yourself »

Browser Support

setInterval() is supported in all browsers:

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
[email protected]

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
[email protected]

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning.
Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness
of all content. While using W3Schools, you agree to have read and accepted our terms of use , cookie and privacy policy .

W3Schools is Powered by W3.CSS .