Comparison of JavaScript engines

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

Explanation of tables[edit]

See List of ECMAScript engines for a full list.

Values[edit]

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.

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[edit]

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[edit]

Global object[edit]

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[edit]

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[edit]

Implementation of function objects
Function object	MSHTML	Gecko	WebKit	Presto	Blink
Called as function
`Function([[p1 [, p2 [, ...]],] body])`	?	Yes	Yes	?	Yes
Called as constructor
`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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

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[edit]

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	?

References[edit]

↑ E4X, Mozilla
↑ ECMAScript 5 Arrays, Microsoft, archived from the original on 2010-06-27, retrieved 2010-06-24 Unknown parameter |url-status= ignored (help)

External links[edit]

Webdevout – mostly covers Windows browsers. Extensive bug testing.

This article "Comparison of JavaScript engines" is from Wikipedia. The list of its authors can be seen in its historical. Articles copied from Draft Namespace on Wikipedia could be seen on the Draft Namespace of Wikipedia and not main one.

[1] E4X, Mozilla

[2] ECMAScript 5 Arrays, Microsoft, archived from the original on 2010-06-27, retrieved 2010-06-24 Unknown parameter |url-status= ignored (help)

[1]

[2]

v t e JavaScript
Code analysis	ESLint JSHint JSLint
Transcompilers	Babel.js CoffeeScript Dart Emscripten Google Closure Compiler Google Web Toolkit Morfik TypeScript AtScript Opa Nim Haxe ClojureScript WebSharper
Concepts	Ajax Client-side Dynamic HTML JavaScript library JavaScript syntax Unobtrusive JavaScript
Debuggers	Firebug Komodo IDE Microsoft Script Debugger Microsoft Script Editor Opera Dragonfly Web Inspector
Doc generators	JSDoc
Editors (comparison)	Ace Cloud9 IDE Atom CodeMirror Light Table Brackets Koding PhpStorm Orion Visual Studio Visual Studio Express Visual Studio Code Visual Studio Team Services
Engines	Comparison of engines DOM support List of ECMAScript engines List of JavaScript engines
Frameworks	Comparison of JavaScript frameworks List of JavaScript libraries
Related technologies	Cascading Style Sheets Document Object Model HTML JSON WebAssembly
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Unit testing	Jasmine Mocha QUnit List of JavaScript unit testing frameworks Jest
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