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Window setInterval() Method

Window Object Reference Window Object

Example

Alert "Hello" every 3 seconds (3000 milliseconds):

setInterval(function(){alert("Hello")}, 3000);

Try it yourself »


Definition and Usage

The setInterval() method calls a function or evaluates an expression at specified intervals (in milliseconds).

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

The ID value returned by setInterval() is used as the parameter for the clearInterval() method.

Tip: 1000 ms = 1 second.

Tip: To execute a function only once, after a specified number of milliseconds, use the setTimeout() method.


Browser Support

Internet Explorer Firefox Opera Google Chrome Safari

The setInterval() method is supported in all major browsers.


Syntax

setInterval(function,milliseconds,lang)

Parameter Values

Parameter Description
function Required. The function that will be executed
milliseconds Required. The intervals (in milliseconds) on how often to execute the code
lang Optional. JScript | VBScript | JavaScript

Return Value

An integer with the ID value of the timer that is set. Use this value with the clearInterval() method to cancel the timer.


More Examples

Example

Display the current time (the setInterval() method will execute the function once every 1 second, just like a digital watch):

var myVar = setInterval(function(){myTimer()}, 1000);

function myTimer() {
    var d = new Date();
    var t = d.toLocaleTimeString();
    document.getElementById("demo").innerHTML = t;
}

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Example

Using clearInterval() to stop time:

var myVar = setInterval(function(){myTimer()}, 1000);

function myTimer() {
    var d = new Date();
    var t = d.toLocaleTimeString();
    document.getElementById("demo").innerHTML = t;
}

function myStopFunction() {
    clearInterval(myVar);
}

Try it yourself »


Window Object Reference Window Object

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