WorkerGlobalScope: setInterval() method

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨July 2015⁩.

* Some parts of this feature may have varying levels of support.

Note: This feature is available in Web Workers.

Warning: When the code parameter is used, this method dynamically executes its value as JavaScript. APIs like this are known as injection sinks, and are potentially a vector for cross-site-scripting (XSS) attacks.

You can mitigate this risk by always assigning TrustedScript objects instead of strings and enforcing trusted types. See Security considerations in Window.setInterval() for more information.

The setInterval() method of the WorkerGlobalScope interface repeatedly calls a function or executes a code snippet, with a fixed time delay between each call.

It is commonly used to set a delay for functions that are executed again and again, such as animations. You can cancel the interval using clearInterval(). See Window.setInterval() for more information.

Note that if you wish to have your function called once after the specified delay, use setTimeout().

Syntax

setInterval(code)
setInterval(code, delay)

setInterval(func)
setInterval(func, delay)
setInterval(func, delay, arg1)
setInterval(func, delay, arg1, arg2)
setInterval(func, delay, arg1, arg2, /* …, */ argN)

Parameters

func: A function to be executed every delay milliseconds. The first execution happens after delay milliseconds.
code: A TrustedScript or a string of arbitrary code that is compiled and executed every delay milliseconds. This can be used instead of passing a function, but is strongly discouraged for the same reasons that make using eval() a security risk.
delay Optional: The delay time between executions of the specified function or code, in milliseconds. Defaults to 0 if not specified. See Delay restrictions in Window.setInterval for details on the permitted range of delay values.
arg1, …, argN Optional: Additional arguments which are passed through to the function specified by func once the timer expires.

Return value

A positive integer (typically within the range of 1 to 2,147,483,647) that uniquely identifies the interval timer created by the call.

This identifier, often referred to as an "interval ID", can be passed to clearInterval() to stop the repeated execution of the specified function.

Exceptions

SyntaxError: The code can't be parsed as a script.
TypeError: Thrown if the code parameter is set to a string when Trusted Types are enforced by CSP and no default policy is defined. It is also thrown if the first parameter is not one of the supported types: a function, string or TrustedScript.