Comparison of JavaScript engines

Last updated September 10, 2022

The following tables compare standards support for some notable JavaScript/ECMAScript engines used in web browsers.

Explanation of tables

See List of ECMAScript engines for a full list.

Values

These indicate the level of support for the given item in each engine. By default, the most recent version of the engine is implied. However, a specific version number can be listed; when this indicates full support, it's the initial version of the engine fully supporting the item.

Legend
Value	Meaning
Yes	Fully supported
No	Has never been supported
Partial	Only some values are supported
Incorrect	Not implemented correctly in all cases
Experimental	May be incomplete or buggy
Nightly build	Currently in development; full support is expected
Depends	Only supported for the specified conditions
Dropped	No longer supported

ECMAScript version support

Overview of ECMAScript version support
Browser engine	MSHTML	Gecko	WebKit	Presto	Blink
Corresponding JavaScript engine	JScript / Chakra	SpiderMonkey	JavaScriptCore	Linear B / Futhark / Carakan	V8
ECMAScript Edition 3	Yes	0.6	Yes	1.0	Yes
ECMAScript Edition 5	5.0	2.0	Partial	Yes	Yes
ECMAScript Edition 6	?	?	?	?	?
JavaScript 1.5 extensions	No	0.6	Yes	1.0	Yes
JavaScript 1.6 extensions (excluding E4X)	No	1.8	Partial	Partial	Partial
JavaScript 1.7 extensions	No	1.8.1	No	Partial	No
JavaScript 1.8 extensions	No	1.9	Partial	No	Partial
JavaScript 1.8.1 extensions	No	1.9.1	No	No	No
JScript .NET extensions	No	No	No	No	No
ActionScript extensions	No	No	No	No	No
E4X	No	Dropped^[1]	No	No	No

Standard library

Global object

Implementation of global objects
Global object	MSHTML	Gecko	WebKit	Presto	Blink
Value properties
`NaN`	4.0	0.6	Yes	Yes	Yes
`Infinity`	4.0	0.6	Yes	Yes	Yes
`undefined`	5.5	0.6	Yes	Yes	Yes
Function properties
`eval(x)`	3.0	0.6	Yes	Yes	Yes
`parseInt(string [, radix])`	3.0	0.6	Yes	Yes	Yes
`parseFloat(string)`	3.0	0.6	Yes	Yes	Yes
`isNaN(number)`	4.0	0.6	Yes	Yes	Yes
`isFinite(number)`	4.0	0.6	Yes	Yes	Yes
URI handling functions
`decodeURI(encodedURI)`	5.5	0.6	Yes	Yes	Yes
`decodeURIComponent(encodedURIComponent)`	5.5	0.6	Yes	Yes	Yes
`encodeURI(uri)`	5.5	0.6	Yes	Yes	Yes
`encodeURIComponent(uriComponent)`	5.5	0.6	Yes	Yes	Yes
Constructor properties
`Object`	4.0	Yes	Yes	Yes	Yes
`Function`	4.0	Yes	Yes	Yes	Yes
`Array`	4.0	Yes	Yes	Yes	Yes
`String`	3.0	Yes	Yes	Yes	Yes
`Boolean`	3.0	Yes	Yes	Yes	Yes
`Number`	3.0	Yes	Yes	Yes	Yes
`Date`	3.0	Yes	Yes	Yes	Yes
`RegExp`	4.0	Yes	Yes	Yes	Yes
`Error`	5.0	Yes	Yes	Yes	Yes
`EvalError`	5.0	Yes	Yes	Yes	Yes
`RangeError`	5.0	Yes	Yes	Yes	Yes
`ReferenceError`	5.0	Yes	Yes	Yes	Yes
`SyntaxError`	5.0	Yes	Yes	Yes	Yes
`TypeError`	5.0	Yes	Yes	Yes	Yes
`URIError`	5.0	Yes	Yes	Yes	Yes
Other properties
`Math`	3.0	Yes	Yes	Yes	Yes
Additional properties
`escape(string)`	3.0	Yes	Yes	Yes	Yes
`unescape(string)`	3.0	Yes	Yes	Yes	Yes

Object object

Implementation of object objects
Object object	MSHTML	Gecko	WebKit	Presto	Blink
Called as function
`Object([value])`	Yes	Yes	Yes	Yes	Yes
Called as constructor
`new Object([value])`	4.0	Yes	Yes	Yes	Yes
Properties
`prototype`	4.0	Yes	Yes	Yes	Yes
Properties of prototype
`constructor`	4.0	Yes	Yes	Yes	Yes
`toString()`	4.0	Yes	Yes	Yes	Yes
`toLocaleString()`	4.0	Yes	Yes	Yes	Yes
`valueOf()`	4.0	Yes	Yes	Yes	Yes
`hasOwnProperty(V)`	5.5	Yes	3	Yes	Yes
`isPrototypeOf(V)`	5.5	Yes	3	Yes	Yes
`propertyIsEnumerable(V)`	5.5	Yes	3	Yes	Yes

Function object

Implementation of function objects
Function object	MSHTML	Gecko	WebKit	Presto	Blink
Called as function
{{code\|Function([[p1 [, p2 [, ...]],] body])}}	?	Yes	Yes	?	Yes
Called as constructor
{{code\|new Function([[p1 [, p2 [, ...]],] body])}}	4.0	1.0	Yes	1.0	Yes
Properties
`length`	?	1.0	Yes	Yes	Yes
`prototype`	4.0	1.0	Yes	1.0	Yes
Properties of prototype
`length`	?	1.0	Yes	?	Yes
`constructor`	4.0	1.0	Yes	1.0	Yes
`toString()`	4.0	1.0	Yes	1.0	Yes
`apply(thisArg, argArray)`	4.0	1.0	Yes	1.0	Yes
`call(thisArg [, arg1 [, arg2 [, ...]]])`	4.0	1.0	Yes	1.0	Yes
Properties of instances
`length`	4.0	1.0	Yes	1.0	Yes
`prototype`	4.0	1.0	Yes	1.0	Yes

Array object

Implementation of array objects
Array object	MSHTML	Gecko	WebKit	Presto	Blink
Called as function
`Array([item1 [, item2 [, ...]]])`	Yes	Yes	Yes	Yes	Yes
Called as constructor
`new Array([item1, item2 [, ...]])`	4.0	1.0	Yes	1.0	Yes
`new Array(len)`	4.0	1.0	Yes	1.0	Yes
Properties
`prototype`	4.0	1.0	Yes	1.0	Yes
Properties of prototype
`constructor`	4.0	1.0	Yes	1.0	Yes
`toString()`	4.0	1.0	Yes	1.0	Yes
`toLocaleString()`	5.5	1.0	Yes	1.0	Yes
`concat([item1 [, item2 [,...]]])`	4.0	1.0	Yes	1.0	Yes
`join(separator)`	4.0	1.0	Yes	1.0	Yes
`pop()`	5.5	1.0	Yes	1.0	Yes
`push([item1 [, item2 [,...]]])`	5.5	1.0	Yes	1.0	Yes
`reverse()`	4.0	1.0	Yes	1.0	Yes
`shift()`	5.5	1.0	Yes	1.0	Yes
`slice(start, end)`	4.0	1.0	Yes	1.0	Yes
`sort(comparefn)`	4.0	1.0	Yes	1.0	Yes
`splice(start, deleteCount [, item1 [, item2 [, ...]]])`	5.5	1.0	Yes	1.0	Yes
`unshift([item1 [, item2 [, ...]]])`	5.5	1.0	Yes	1.0	Yes
`indexOf(searchElement[, fromIndex])`	9.0^[2]	1.8	522	2.1	Yes
`lastIndexOf(searchElement[, fromIndex])`		1.8	522	2.1	Yes
`filter(callback[, thisObject])`		1.8	522	2.1	Yes
`forEach(callback[, thisObject])`		1.8	522	2.1	Yes
`every(callback[, thisObject])`		1.8	522	2.1	Yes
`map(callback[, thisObject])`		1.8	522	2.1	Yes
`some(callback[, thisObject])`		1.8	522	2.1	Yes
`reduce(callback[, initialValue])`		1.9	528	2.5.22	Yes
`reduceRight(callback[, initialValue])`		1.9	528	2.5.22	Yes
Properties of instances
`length`	4.0	1.0	Yes	1.0	Yes

String object

Implementation of string objects
String object	MSHTML	Gecko	WebKit	Presto	Blink
Called as function
`String([value])`	Yes	Yes	Yes	Yes	Yes
Called as constructor
`new String([value])`	3.0	1.0	Yes	1.0	Yes
Properties
`prototype`	4.0	1.0	Yes	1.0	Yes
`fromCharCode([char0 [, char1 [, ...]]])`	4.0	1.0	Yes	1.0	Yes
Properties of prototype
`constructor`	4.0	1.0	Yes	1.0	Yes
`toString()`	3.0	1.0	Yes	1.0	Yes
`valueOf()`	3.0	1.0	Yes	1.0	Yes
`charAt(pos)`	3.0	1.0	Yes	1.0	Yes
`charCodeAt(pos)`	5.5	1.0	Yes	1.0	Yes
`concat([string1 [, string2 [, ...]]])`	4.0	1.0	Yes	1.0	Yes
`indexOf(searchString, position)`	3.0	1.0	Yes	1.0	Yes
`lastIndexOf(searchString, position)`	3.0	1.0	Yes	1.0	Yes
`localeCompare(that)`	5.5	1.0	Yes	1.0	Yes
`match(regexp)`	4.0	1.0	Yes	1.0	Yes
`replace(searchValue, replaceValue)`	3.0	1.0	Yes	1.0	Yes
`search(regexp)`	4.0	1.0	Yes	1.0	Yes
`slice(start, end)`	4.0	1.0	Yes	1.0	Yes
`split(separator, limit)`	4.0	1.0	Yes	1.0	Yes
`substring(start, end)`	3.0	1.0	Yes	1.0	Yes
`toLowerCase()`	3.0	1.0	Yes	1.0	Yes
`toLocaleLowerCase(comparefn)`	3.0	1.0	Yes	1.0	Yes
`toUpperCase()`	3.0	1.0	Yes	1.0	Yes
`toLocaleUpperCase()`	3.0	1.0	Yes	1.0	Yes
Additional properties of prototype
`substr(start, length)`	4.0	1.0	Yes	1.0	Yes
Properties of instances
`length`	3.0	1.0	Yes	1.0	Yes

Boolean object

Implementation of Boolean objects
Boolean object	MSHTML	Gecko	WebKit	Presto	Blink
Called as function
`Boolean([value])`	Yes	Yes	Yes	Yes	Yes
Called as constructor
`new Boolean([value])`	3.0	Yes	Yes	Yes	Yes
Properties
`prototype`	4.0	Yes	Yes	Yes	Yes
Properties of prototype
`constructor`	4.0	Yes	Yes	Yes	Yes
`toString()`	4.0	Yes	Yes	Yes	Yes
`valueOf()`	4.0	Yes	Yes	Yes	Yes

Number object

Implementation of number objects
Number object	MSHTML	Gecko	WebKit	Presto
Called as function
`Number([value])`	?	Yes	Yes	?
Called as constructor
`new Number([value])`	3.0	1.0	Yes	1.0
Properties
`prototype`	4.0	1.0	Yes	1.0
`MAX_VALUE`	4.0	1.0	Yes	1.0
`MIN_VALUE`	4.0	1.0	Yes	1.0
`NaN`	4.0	1.0	Yes	1.0
`NEGATIVE_INFINITY`	4.0	1.0	Yes	1.0
`POSITIVE_INFINITY`	4.0	1.0	Yes	1.0
Properties of prototype
`constructor`	4.0	1.0	Yes	1.0
`toString([radix])`	4.0	1.0	Yes	1.0
`toLocaleString()`	5.5	1.0	Yes	1.0
`valueOf()`	4.0	1.0	Yes	1.0
`toFixed(fractionDigits)`	5.5	1.0	Yes	1.0
`toExponential(fractionDigits)`	5.5	1.0	Yes	1.0
`toPrecision(precision)`	5.5	1.0	Yes	1.0

Math object

Implementation of math objects
Math object	MSHTML	Gecko	WebKit	Presto
Value properties
`E`	3.0	1.0	Yes	1.0
`LN10`	3.0	1.0	Yes	1.0
`LN2`	3.0	1.0	Yes	1.0
`LOG2E`	3.0	1.0	Yes	1.0
`LOG10E`	3.0	1.0	Yes	1.0
`PI`	Yes	Yes	Yes	Yes
`SQRT1_2`	3.0	1.0	Yes	1.0
`SQRT2`	Yes	Yes	Yes	Yes
Function properties
`abs(x)`	3.0	1.0	Yes	1.0
`acos(x)`	3.0	1.0	Yes	1.0
`asin(x)`	3.0	1.0	Yes	1.0
`atan(x)`	3.0	1.0	Yes	1.0
`atan2(y, x)`	3.0	1.0	Yes	1.0
`ceil(x)`	3.0	1.0	Yes	1.0
`cos(x)`	3.0	1.0	Yes	1.0
`exp(x)`	3.0	1.0	Yes	1.0
`floor(x)`	3.0	1.0	Yes	1.0
`log(x)`	3.0	1.0	Yes	1.0
`max([value1 [, value2 [, ...]]])`	3.0	1.0	Yes	1.0
`min([value1 [, value2 [, ...]]])`	3.0	1.0	Yes	1.0
`pow(x, y)`	3.0	1.0	Yes	1.0
`random()`	3.0	1.0	Yes	1.0
`round(x)`	3.0	1.0	Yes	1.0
`sin(x)`	3.0	1.0	Yes	1.0
`sqrt(x)`	3.0	1.0	Yes	1.0
`tan(x)`	3.0	1.0	Yes	1.0

Date object

Implementation of date objects
Date object	MSHTML	Gecko	WebKit	Presto
Called as function
`Date ([year [, month [, date [, hours [, minutes [, seconds [, ms ]]]]]]])`	?	?	?	?
Called as constructor
`new Date (year, month [, date [, hours [, minutes [, seconds [, ms ]]]]])`	4.0	1.0	Yes	1.0
`new Date (value)`	4.0	1.0	Yes	1.0
`new Date ()`	4.0	1.0	Yes	1.0
Properties
`prototype`	4.0	1.0	Yes	1.0
`parse(string)`	3.0	1.0	Yes	1.0
`UTC (year, month [, date [, hours [, minutes [, seconds [, ms ]]]]])`	3.0	1.0	Yes	1.0
Properties of prototype
`constructor`	4.0	1.0	Yes	1.0
`toString()`	4.0	1.0	Yes	1.0
`toDateString()`	4.0	1.0	Yes	1.0
`toTimeString()`	4.0	1.0	Yes	1.0
`toLocaleString()`	4.0	1.0	Yes	1.0
`toLocaleDateString()`	4.0	1.0	Yes	1.0
`toLocaleTimeString()`	4.0	1.0	Yes	1.0
`valueOf()`	4.0	1.0	Yes	1.0
`getTime()`	3.0	1.0	Yes	1.0
`getFullYear()`	4.0	1.0	Yes	1.0
`getMonth()`	3.0	1.0	Yes	1.0
`getUTCMonth()`	4.0	1.0	Yes	1.0
`getDate()`	3.0	1.0	Yes	1.0
`getUTCDate()`	4.0	1.0	Yes	1.0
`getDay()`	3.0	1.0	Yes	1.0
`getUTCDay()`	4.0	1.0	Yes	1.0
`getHours()`	3.0	1.0	Yes	1.0
`getUTCHours()`	4.0	1.0	Yes	1.0
`getMinutes()`	3.0	1.0	Yes	1.0
`getUTCMinutes()`	4.0	1.0	Yes	1.0
`getSeconds()`	3.0	1.0	Yes	1.0
`getUTCSeconds()`	4.0	1.0	Yes	1.0
`getMilliseconds()`	4.0	1.0	Yes	1.0
`getUTCMilliseconds()`	4.0	1.0	Yes	1.0
`getTimezoneOffset()`	4.0	1.0	Yes	1.0
`setTime(time)`	3.0	1.0	Yes	1.0
`setMilliseconds(ms)`	4.0	1.0	Yes	1.0
`setUTCMilliseconds(ms)`	4.0	1.0	Yes	1.0
`setSeconds(sec [, ms])`	3.0	1.0	Yes	1.0
`setUTCSeconds(sec [, ms])`	4.0	1.0	Yes	1.0
`setMinutes(min [, sec [, ms]])`	3.0	1.0	Yes	1.0
`setUTCMinutes(min [, sec [, ms]])`	4.0	1.0	Yes	1.0
`setHours(hour [, min [, sec [, ms]]])`	4.0	1.0	Yes	1.0
`setUTCHours(hour [, min [, sec [, ms]]])`	4.0	1.0	Yes	1.0
`setDate(date)`	4.0	1.0	Yes	1.0
`setUTCDate(date)`	4.0	1.0	Yes	1.0
`setMonth(month [, date])`	3.0	1.0	Yes	1.0
`setUTCMonth(month [, date])`	4.0	1.0	Yes	1.0
`setFullYear(year [, month [, date]])`	4.0	1.0	Yes	1.0
`setUTCFullYear(year [, month [, date]])`	4.0	1.0	Yes	1.0
`toUTCString()`	4.0	1.0	Yes	1.0
Additional properties of prototype
`getYear()`	3.0	1.0	Yes	1.0
`setYear(year)`	3.0	1.0	Yes	1.0
`toGMTString()`	4.0	1.0	Yes	1.0

RegExp object

Implementation of RegExp objects
RegExp object	MSHTML	Gecko	WebKit	Presto
Called as function
`RegExp (pattern, flags)`	?	?	?	?
Called as constructor
`new RegExp (pattern, flags)`	4.0	1.0	Yes	1.0
Properties
`prototype`	4.0	1.0	Yes	1.0
Properties of prototype
`constructor`	4.0	1.0	Yes	1.0
`exec(string)`	4.0	1.0	Yes	1.0
`test(string)`	4.0	1.0	Yes	1.0
`toString()`	4.0	1.0	Yes	1.0
Properties of instances
`source`	4.0	1.0	Yes	1.0
`global`	4.0	1.0	Yes	1.0
`ignoreCase`	5.5	1.0	Yes	1.0
`multiline`	5.5	1.0	Yes	1.0
`lastIndex`	4.0	1.0	Yes	1.0

Error object

Implementation of error objects
Error object	MSHTML	Gecko	WebKit	Presto
Called as function
`Error (message)`	?	?	?	?
Called as constructor
`new Error (message)`	5.0	1.0	Yes	1.0
Properties
`prototype`	5.0	1.0	Yes	1.0
Properties of prototype
`constructor`	5.0	1.0	Yes	1.0
`name`	5.5	1.0	Yes	1.0
`message`	5.5	1.0	Yes	1.0
`toString()`	5.0	1.0	Yes	1.0

NativeError objects

Implementation of NativeError objects
NativeError object	MSHTML	Gecko	WebKit	Presto
Called as function
`EvalError (message)`	?	1.0	Yes	?
`RangeError (message)`	?	1.0	Yes	?
`ReferenceError (message)`	?	1.0	Yes	?
`SyntaxError (message)`	?	1.0	Yes	?
`TypeError (message)`	?	1.0	Yes	?
`URIError (message)`	?	1.0	Yes	?
Called as constructor
`new EvalError (message)`	?	1.0	Yes	?
`new RangeError (message)`	?	1.0	Yes	?
`new ReferenceError (message)`	?	1.0	Yes	?
`new SyntaxError (message)`	?	1.0	Yes	?
`new TypeError (message)`	?	1.0	Yes	?
`new URIError (message)`	?	1.0	Yes	?
Properties
`prototype`	?	1.0	?	?
Properties of prototype
`constructor`	?	1.0	?	?
`name`	?	1.0	Yes	?
`message`	?	1.0	Yes	?

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References

↑ E4X, Mozilla
↑ ECMAScript 5 Arrays, Microsoft, archived from the original on 2010-06-27, retrieved 2010-06-24

External links

Webdevout – mostly covers Windows browsers. Extensive bug testing.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[1] E4X, Mozilla

[2] ECMAScript 5 Arrays, Microsoft, archived from the original on 2010-06-27, retrieved 2010-06-24

[1]

[2]

v t e JavaScript
Code analysis	ESLint JSHint JSLint
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