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requestIdleCallback
Last updated on : 2023-03-20
Note:
requestIdleCallback shows a browser compatibility score of 75. This is a collective score out of 100 to represent browser support of a web technology. The higher this score is, the greater is the browser compatibility. The browser compatibility score is not a 100% reflection for every browser and the web technology support. However, it does give you an estimate on how much you should rely on a particular web technology in terms of browser compatibility.
Overview
This API provides a mechanism for executing JavaScript code in a browser context when the browser is idle. The API is designed to reduce the need for polling, allowing developers to queue up work to happen while the browser's resources are otherwise occupied.
Specifications
Cooperative Scheduling of Background Tasks # the-requestidlecallback-method
Syntax
window.requestIdleCallback(callback);
window.requestIdleCallback(callback, options);
Code snippets
basic.html
Source:basic.html 
1<!DOCTYPE html>2<title>window.requestIdleCallback exists</title>3<link rel="author" title="Ross McIlroy" href="mailto:rmcilroy@chromium.org" />4<script src="/resources/testharness.js"></script>5<script src="/resources/testharnessreport.js"></script>6<script>7test(function() {8 assert_equals(typeof window.requestIdleCallback, "function");9}, "window.requestIdleCallback is defined", {assert: "The window.requestIdleCallback function is used to request callbacks during browser-defined idle time."});10test(function() {11 assert_equals(typeof window.cancelIdleCallback, "function");12}, "window.cancelIdleCallback is defined", {assert: "The window.cancelIdleCallback function is used to cancel callbacks scheduled via requestIdleCallback."});13test(function() {14 assert_equals(typeof window.requestIdleCallback(function() {}), "number");15}, "window.requestIdleCallback() returns a number", {assert: "The requestIdleCallback method MUST return a long"});16test(function() {17 assert_equals(typeof window.cancelIdleCallback(1), "undefined");18}, "window.cancelIdleCallback() returns undefined", {assert: "The cancelIdleCallback method MUST return void"});19async_test(function() {20 // Check whether requestIdleCallback schedules a callback which gets executed21 // and the deadline argument is passed correctly.22 requestIdleCallback(this.step_func_done(function(deadline) {23 assert_equals(arguments.length, 1, "Only one argument should be passed to callback.");24 assert_class_string(deadline, "IdleDeadline");25 assert_equals(typeof deadline.timeRemaining, "function", "IdleDeadline.timeRemaining MUST be a function which returns the time remaining in milliseconds");26 assert_equals(typeof deadline.timeRemaining(), "number", "IdleDeadline.timeRemaining MUST return a double of the time remaining in milliseconds");27 assert_true(deadline.timeRemaining() <= 50, "IdleDeadline.timeRemaining() MUST be less than or equal to 50ms in the future.");28 assert_equals(typeof deadline.didTimeout, "boolean", "IdleDeadline.didTimeout MUST be a boolean");29 assert_false(deadline.didTimeout, "IdleDeadline.didTimeout MUST be false if requestIdleCallback wasn't scheduled due to a timeout");30 }));31}, 'requestIdleCallback schedules callbacks');32async_test(function() {33 // Check whether requestIdleCallback schedules a callback which gets executed34 // and the deadline argument is passed correctly.35 var handle = requestIdleCallback(this.step_func(function(deadline) {36 assert_unreached("callback should not be called if canceled with cancelIdleCallback");37 }));38 cancelIdleCallback(handle);39 setTimeout(this.step_func(function() {40 this.done();41 }), 200);42}, 'cancelIdleCallback cancels callbacks');43</script>44<h1>Basic requestIdleCallback Tests</h1>...
Browser Compatibility
- requestIdleCallback on IE is fully supported on None of the versions, partially supported on None of the versions, and not supported on 5.5-11 IE versions.
- requestIdleCallback on Edge is fully supported on 79-111, partially supported on None of the versions, and not supported on 12-18 Edge versions.
- requestIdleCallback on Firefox is fully supported on 55-113, partially supported on None of the versions, and not supported on 2-54 Firefox versions.
- requestIdleCallback on Chrome is fully supported on 47-114, partially supported on None of the versions, and not supported on 4-46 Chrome versions.
- requestIdleCallback on Safari is fully supported on None of the versions, partially supported on None of the versions, and not supported on 3.2-16.4 Safari versions.
- requestIdleCallback on Opera is fully supported on 34-95, partially supported on None of the versions, and not supported on 9.5-33 Opera versions.
- requestIdleCallback on Safari on iOS is fully supported on None of the versions, partially supported on None of the versions, and not supported on 3.2-16.4 Safari on iOS versions.
- requestIdleCallback on Android Browser is fully supported on 97-111, partially supported on None of the versions, and not supported on 2.1-4 Android Browser versions.
- requestIdleCallback on Opera Mobile is fully supported on 64-73, partially supported on None of the versions, and not supported on 10-12 Opera Mobile versions.
- requestIdleCallback on Chrome for Android is fully supported on 97-111, partially supported on None of the versions, and not supported on below 97 Chrome for Android versions.
- requestIdleCallback on Firefox for Android is fully supported on 95-110, partially supported on None of the versions, and not supported on below 95 Firefox for Android versions.
- requestIdleCallback on Samsung Internet is fully supported on 5-20, partially supported on None of the versions, and not supported on 4-4 Samsung Internet versions.
75
High
Browser Compatibility Score
IELow
EdgeHigh
FirefoxHigh
ChromeHigh
SafariLow
OperaHigh
Safari on iOSLow
Android BrowserHigh
Browser Support For Android Browser Versions
97-111
Fully
-
Partially
2.1-4
No Support
Opera MobileHigh
Chrome for AndroidHigh
Browser Support For Chrome for Android Versions
97-111
Fully
-
Partially
-
No Support
Firefox for AndroidHigh
Browser Support For Firefox for Android Versions
95-110
Fully
-
Partially
-
No Support
Samsung InternetHigh
Browser Support For Samsung Internet Versions
5-20
Fully
-
Partially
4-4
No Support
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Last Modified date
2023-03-20
Chrome
Safari
Firefox
Internet Explorer
Opera
EdgeReferences
Data sourced from
- - The World Wide Web Consortium (W3C) (https://www.w3.org/TR/)
- - CanIuse (https://caniuse.com/)
- - Mozzila MDN Web Docs (https://developer.mozilla.org/en-US/)
- - Web.Dev (https://web.dev/)
- - Chrome Platform Status (https://chromestatus.com/features)
- - WebKit Feature Status (https://webkit.org/status/)
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