Features and browsers supported

We test browser support with a test suite for each feature. A browser is considered compliant only if it passes all the tests, so this is a reasonably comprehensive test rather than a naive feature-detect. To view the test suite for a feature in the browser you're using right now, click the Tests link in the feature list. The results below are generated using browsers hosted by Sauce Labs.

Feature list

Key: Feature missing, Feature supported with Polyfill service, Feature supported natively, Included by default
Data Live test	IE	Firefox	Chrome	Safari
Array.from¶ 0.9KB	78910111213	203033414244	303540424648	5.189
Array.isArray¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Array.of¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Array.prototype.@@iterator¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Array.prototype.contains¶ 0.1KB	78910111213	203033414244	303540424648	5.189
This feature was deprecated since it was found to break older versions of Mootools. Use `Array.prototype.includes` instead.
Array.prototype.entries¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Array.prototype.every¶ 0.3KB	78910111213	203033414244	303540424648	5.189
Array.prototype.fill¶ 0.5KB	78910111213	203033414244	303540424648	5.189
Array.prototype.filter¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Array.prototype.find¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Array.prototype.findIndex¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Array.prototype.forEach¶ 0.3KB	78910111213	203033414244	303540424648	5.189
Array.prototype.includes¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Array.prototype.indexOf¶ 0.3KB	78910111213	203033414244	303540424648	5.189
Array.prototype.keys¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Array.prototype.lastIndexOf¶ 0.3KB	78910111213	203033414244	303540424648	5.189
Array.prototype.map¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Array.prototype.reduce¶ 0.5KB	78910111213	203033414244	303540424648	5.189
Array.prototype.reduceRight¶ 0.5KB	78910111213	203033414244	303540424648	5.189
Array.prototype.some¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Array.prototype.values¶ 0.1KB	78910111213	203033414244	303540424648	5.189
AudioContext¶ 0.9KB	78910111213	203033414244	303540424648	5.189
CustomEvent¶ 0.5KB	78910111213	203033414244	303540424648	5.189
DOMTokenList¶ 0.3KB	78910111213	203033414244	303540424648	5.189
DOMTokenList.prototype.@@iterator¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Date.now¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Date.prototype.toISOString¶ 0.3KB	78910111213	203033414244	303540424648	5.189
Document¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Element¶ 1.3KB	78910111213	203033414244	303540424648	5.189
Element.prototype.after¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Element.prototype.append¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Element.prototype.before¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Element.prototype.classList¶ 1.0KB	78910111213	203033414244	303540424648	5.189
Element.prototype.cloneNode¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Element.prototype.closest¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Element.prototype.matches¶ 0.3KB	78910111213	203033414244	303540424648	5.189
Element.prototype.placeholder¶ 1.3KB	78910111213	203033414244	303540424648	5.189
Element.prototype.prepend¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Element.prototype.remove¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Element.prototype.replaceWith¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Event¶ 3.0KB	78910111213	203033414244	303540424648	5.189
Where necessary, also adds the EventTarget methods `addEventListener`, `removeEventListener` and `dispatchEvent`.
Event.DOMContentLoaded¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Event.focusin¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Event.hashchange¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Function.prototype.bind¶ 1.0KB	78910111213	203033414244	303540424648	5.189
HTMLDocument¶ 0.1KB	78910111213	203033414244	303540424648	5.189
HTMLPictureElement¶ 16.9KB	78910111213	203033414244	303540424648	5.189
IntersectionObserver¶ 6.2KB	78910111213	203033414244	303540424648	5.189
Intl¶ 33.9KB	78910111213	203033414244	303540424648	5.189
Locales must be specified separately by prefixing the locale name with `Intl.~locale`, eg `Intl.~locale.en-GB`.
JSON¶ 3.9KB	78910111213	203033414244	303540424648	5.189
Map¶ 1.7KB	78910111213	203033414244	303540424648	5.189
For compatibility with very old engines, `Map.prototype.delete` must be accessed using square bracket notation because 'delete' is a reserved word. `myMap.delete()` is an error in IE8. Use `myMap['delete']()` instead. The test suite for this polyfill is derived from work of Andrea Giammarchi which is published under an MIT licence
Math.acosh¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.asinh¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.atanh¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.cbrt¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.clz32¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.cosh¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.expm1¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.hypot¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.imul¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.log10¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.log1p¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.log2¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.sign¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.sinh¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.tanh¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Math.trunc¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Node.prototype.contains¶ 0.3KB	78910111213	203033414244	303540424648	5.189
NodeList.prototype.@@iterator¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Number.isNaN¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Object.assign¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Object.create¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Object.defineProperties¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Object.defineProperty¶ 1.1KB	78910111213	203033414244	303540424648	5.189
In browsers that have no hooks to define getter functions (notably IE <= 8), attempting to defineProperty with a getter or setter function will fail. Since failing silently would likely break your application, we throw an exception. In IE8, this can be hard to diagnose because the console will just say 'Exception thrown and not caught'
Object.getOwnPropertyDescriptor¶ 1.0KB	78910111213	203033414244	303540424648	5.189
Object.getOwnPropertyNames¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Object.getPrototypeOf¶ 0.2KB	78910111213	203033414244	303540424648	5.189
Object.is¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Object.keys¶ 0.5KB	78910111213	203033414244	303540424648	5.189
Object.setPrototypeOf¶ 0.7KB	78910111213	203033414244	303540424648	5.189
Promise¶ 4.4KB	78910111213	203033414244	303540424648	5.189
In IE8, the `catch` method cannot be invoked directly since it is a reserved word. Instead, use `["catch"]` if intend to run your code in IE8
Set¶ 1.4KB	78910111213	203033414244	303540424648	5.189
For compatibility with very old engines, `Set.prototype.delete` must be accessed using square bracket notation because 'delete' is a reserved word. `mySet.delete()` is an error in IE8. Use `mySet['delete']()` instead. The test suite for this polyfill is derived from work of Andrea Giammarchi which is published under an MIT licence
String.prototype.contains¶ 0.1KB	78910111213	203033414244	303540424648	5.189
String.prototype.endsWith¶ 0.1KB	78910111213	203033414244	303540424648	5.189
String.prototype.includes¶ 0.2KB	78910111213	203033414244	303540424648	5.189
String.prototype.repeat¶ 0.3KB	78910111213	203033414244	303540424648	5.189
String.prototype.startsWith¶ 0.1KB	78910111213	203033414244	303540424648	5.189
String.prototype.trim¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol¶ 2.5KB	78910111213	203033414244	303540424648	5.189
Symbol.hasInstance¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.isConcatSpreadable¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.iterator¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.match¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.replace¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.search¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.species¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.split¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.toPrimitive¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.toStringTag¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Symbol.unscopables¶ 0.1KB	78910111213	203033414244	303540424648	5.189
URL¶ 3.8KB	78910111213	203033414244	303540424648	5.189
`searchParams` is not iterable and has no `forEach()`, `entries()`, `keys()`, `values()` methods Polyfill requires Object getters so fails in IE < 8
UserTiming¶ 5.0KB	78910111213	203033414244	303540424648	5.189
WeakMap¶ 0.7KB	78910111213	203033414244	303540424648	5.189
WeakSet¶ 0.4KB	78910111213	203033414244	303540424648	5.189
Window¶ 0.1KB	78910111213	203033414244	303540424648	5.189
XMLHttpRequest¶ 1.1KB	78910111213	203033414244	303540424648	5.189
atob¶ 0.8KB	78910111213	203033414244	303540424648	5.189
console¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.assert¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.clear¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.count¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.debug¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.dir¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.dirxml¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.error¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.exception¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.group¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.groupCollapsed¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.groupEnd¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.info¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.log¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.markTimeline¶ 0.1KB	78910111213	203033414244	303540424648	5.189
Formerly supported by chrome and safari, but deprecated after discussion with Firebug. Use `timeStamp()` instead.
console.table¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.time¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.timeEnd¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.timeStamp¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.timeline¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.timelineEnd¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.trace¶ 0.1KB	78910111213	203033414244	303540424648	5.189
console.warn¶ 0.1KB	78910111213	203033414244	303540424648	5.189
devicePixelRatio¶ 0.1KB	78910111213	203033414244	303540424648	5.189
This polyfill just sets `devicePixelRatio` to 1 without attempting to measure it. Older versions of Firefox are known to incorrectly alter the DPR on user zoom, but we don't (currently) correct for this
document.getElementsByClassName¶ 0.1KB	78910111213	203033414244	303540424648	5.189
document.head¶ 0.1KB	78910111213	203033414244	303540424648	5.189
document.querySelector¶ 0.7KB	78910111213	203033414244	303540424648	5.189
document.visibilityState¶ 0.3KB	78910111213	203033414244	303540424648	5.189
The alias `PageVisibility` works for this feature for backwards compatibility with the name under which it was previously (erroneously) available
fetch¶ 5.6KB	78910111213	203033414244	303540424648	5.189
Makes use of FormData, FileReader and Blob if they exist
getComputedStyle¶ 1.9KB	78910111213	203033414244	303540424648	5.189
localStorage¶ 1.1KB	78910111213	203033414244	303540424648	5.189
location.origin¶ 0.3KB	78910111213	203033414244	303540424648	5.189
matchMedia¶ 1.4KB	78910111213	203033414244	303540424648	5.189
navigator.geolocation¶ 1.2KB	78910111213	203033414244	303540424648	5.189
navigator.sendBeacon¶ 0.4KB	78910111213	203033414244	303540424648	5.189
performance.now¶ 0.1KB	78910111213	203033414244	303540424648	5.189
requestAnimationFrame¶ 0.7KB	78910111213	203033414244	303540424648	5.189
screen.orientation¶ 0.9KB	78910111213	203033414244	303540424648	5.189
In IE <= 8 window.screen is read-only, so the orientation property is not definable
setImmediate¶ 1.6KB	78910111213	203033414244	303540424648	5.189
~html5-elements¶ 2.6KB	78910111213	203033414244	303540424648	5.189
~viewport¶ 0.7KB	78910111213	203033414244	303540424648	5.189

Bundle sizes

The table above lists a data size for each polyfill, which is the size of the polyfill including a feature detect, after minification, and before gzip. Two very important things to remember about these sizes are:

Gzip gets more effective the larger the data is, so the more polyfills you include in the bundle you request, the smaller each individual polyfill is likely to be, once the bundle is gzipped.
Some polyfills have multiple variants. In these cases, the size of the largest variant is shown.

The following table shows the total size of the polyfill bundle for the default set, in all our test browsers:

Browser	Version	Size (raw)	Size (min)	Size (gzip)
chrome	30	43.9KB	20.1KB	6.9KB
chrome	35	31.7KB	13.4KB	4.3KB
chrome	40	18.1KB	7.7KB	2.7KB
chrome	42	16.9KB	7.1KB	2.5KB
chrome	46	11.7KB	5.2KB	1.8KB
chrome	48	11.7KB	5.2KB	1.8KB
firefox	20	45.5KB	21.0KB	7.1KB
firefox	30	9.2KB	3.9KB	1.4KB
firefox	33	5.6KB	2.5KB	0.9KB
firefox	41	4.1KB	1.8KB	0.6KB
firefox	42	4.1KB	1.8KB	0.6KB
firefox	44	4.1KB	1.8KB	0.6KB
ie	7	83.5KB	35.8KB	11.2KB
ie	8	97.0KB	42.6KB	13.3KB
ie	9	62.5KB	30.6KB	10.3KB
ie	10	47.8KB	23.8KB	7.9KB
ie	11	47.2KB	23.4KB	7.9KB
ie	12	24.4KB	13.2KB	4.9KB
ie	13	19.7KB	8.8KB	3.0KB
safari	8	17.9KB	7.5KB	2.6KB
safari	9	14.4KB	6.2KB	2.1KB
safari	5.1	62.9KB	27.0KB	8.9KB
android	4.4	33.6KB	15.2KB	5.5KB
android	4.3	34.0KB	15.4KB	5.5KB
android	4.2	34.0KB	15.4KB	5.5KB
android	4.1	34.0KB	15.4KB	5.5KB
ios_saf	9.1	5.4KB	2.3KB	0.8KB
ios_saf	9.2	5.0KB	2.1KB	0.8KB

Default sets

The alias default includes a set of polyfills that comprise features with high demands, small polyfill sizes, good performance and at least one good native implementation in a stable browser. The set evolves over time to include new features as they become a more stable part of the web platform.

Although you cannot request an immutable version of a polyfill, you can reduce the risk of future releases of the polyfill service breaking compatibility with your code by using an immutable default set. Each time we make a release, if we have changed the features included in the default set we will issue a new immutable alias for the set, which won't change when the default set changes again. The components of these sets are shown below:

Alias	Constituents
`default-3.3`	Array.isArray, Array.prototype.every, Array.prototype.filter, Array.prototype.forEach, Array.prototype.indexOf, Array.prototype.lastIndexOf, Array.prototype.map, Array.prototype.reduce, Array.prototype.reduceRight, Array.prototype.some, atob, CustomEvent, Date.now, Date.prototype.toISOString, Document, document.querySelector, document.visibilityState, DOMTokenList, Element, Element.prototype.classList, Element.prototype.cloneNode, Element.prototype.closest, Element.prototype.matches, Event, Event.DOMContentLoaded, Event.focusin, Event.hashchange, Function.prototype.bind, JSON, Object.assign, Object.create, Object.defineProperties, Object.defineProperty, Object.getOwnPropertyNames, Object.getPrototypeOf, Object.keys, requestAnimationFrame, String.prototype.includes, String.prototype.trim, Window, XMLHttpRequest, ~html5-elements
`default-3.4`	Added Array.from, Array.of, Array.prototype.fill, Element.prototype.after, Element.prototype.append, Element.prototype.before, Element.prototype.prepend, Element.prototype.remove, Element.prototype.replaceWith, Node.prototype.contains, Number.isNaN, Promise, String.prototype.endsWith, String.prototype.startsWith, URL, location.origin
`default-3.5`	Added Object.getOwnPropertyDescriptor
`default-3.6`	Added Map, Set

Features and browsers supported

Feature list

Array.from¶

Array.isArray¶

Array.of¶

Array.prototype.@@iterator¶

Array.prototype.contains¶

Array.prototype.entries¶

Array.prototype.every¶

Array.prototype.fill¶

Array.prototype.filter¶

Array.prototype.find¶

Array.prototype.findIndex¶

Array.prototype.forEach¶

Array.prototype.includes¶

Array.prototype.indexOf¶

Array.prototype.keys¶

Array.prototype.lastIndexOf¶

Array.prototype.map¶

Array.prototype.reduce¶

Array.prototype.reduceRight¶

Array.prototype.some¶

Array.prototype.values¶

AudioContext¶

CustomEvent¶

DOMTokenList¶

DOMTokenList.prototype.@@iterator¶

Date.now¶

Date.prototype.toISOString¶

Document¶

Element¶

Element.prototype.after¶

Element.prototype.append¶

Element.prototype.before¶

Element.prototype.classList¶

Element.prototype.cloneNode¶

Element.prototype.closest¶

Element.prototype.matches¶

Element.prototype.placeholder¶

Element.prototype.prepend¶

Element.prototype.remove¶

Element.prototype.replaceWith¶

Event¶

Event.DOMContentLoaded¶

Event.focusin¶

Event.hashchange¶

Function.prototype.bind¶

HTMLDocument¶

HTMLPictureElement¶

IntersectionObserver¶

Intl¶

JSON¶

Map¶

Math.acosh¶

Math.asinh¶

Math.atanh¶

Math.cbrt¶

Math.clz32¶

Math.cosh¶

Math.expm1¶

Math.hypot¶

Math.imul¶

Math.log10¶

Math.log1p¶

Math.log2¶

Math.sign¶

Math.sinh¶

Math.tanh¶

Math.trunc¶

Node.prototype.contains¶

NodeList.prototype.@@iterator¶

Number.isNaN¶

Object.assign¶

Object.create¶

Object.defineProperties¶

Object.defineProperty¶

Object.getOwnPropertyDescriptor¶

Object.getOwnPropertyNames¶

Object.getPrototypeOf¶

Object.is¶