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Summary
| Pages | No tags | Needs* tags | Missing tags | Editorial reviews | Technical reviews | Outdated pages | Dev-doc-needed bugs | Documentation requests |
|---|---|---|---|---|---|---|---|---|
| 862 | 27 (4%) | 0 (0%) | 27 (4%) | 92 (11%) | 99 (12%) | 83 (10%) | 0 (0%) | 80 (10%) |
See also localization status of this section.
No tags
Found 27 pages. Learn more about how to tag pages.
- Debug
- Debug.debuggerEnabled
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackStarting
- Debug.msTraceAsyncOperationStarting
- Debug.msUpdateAsyncCallbackRelation
- Debug.setNonUserCodeExceptions
- Debug.write
- Enumerator
- Enumerator.atEnd
- Enumerator.item
- Enumerator.moveFirst
- Enumerator.moveNext
- Error.description
- Error.number
- Error.stackTraceLimit
- GetObject
- ScriptEngineBuildVersion
- ScriptEngineMajorVersion
- ScriptEngineMinorVersion
- VBArray
- VBArray.dimensions
- VBArray.getItem
- VBArray.lbound
- VBArray.toArray
- VBArray.ubound
Missing tags
At least missing one of the following: JavaScript
Found 27 pages. Learn more about how to tag pages.
- Debug
- Debug.debuggerEnabled
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackStarting
- Debug.msTraceAsyncOperationStarting
- Debug.msUpdateAsyncCallbackRelation
- Debug.setNonUserCodeExceptions
- Debug.write
- Enumerator
- Enumerator.atEnd
- Enumerator.item
- Enumerator.moveFirst
- Enumerator.moveNext
- Error.description
- Error.number
- Error.stackTraceLimit
- GetObject
- ScriptEngineBuildVersion
- ScriptEngineMajorVersion
- ScriptEngineMinorVersion
- VBArray
- VBArray.dimensions
- VBArray.getItem
- VBArray.lbound
- VBArray.toArray
- VBArray.ubound
Editorial reviews
Found 92 pages. Learn more about how to do an editorial review.
- JavaScript
- A re-introduction to JavaScript (JS tutorial)
- Equality comparisons and sameness
- Introduction to using XPath in JavaScript
- Functions
- Grammar and types
- Indexed collections
- Keyed collections
- Numbers and dates
- Using promises
- JavaScript language resources
- Grouping operator
- delete operator
- Rest parameters
- getter
- TypeError: can't access property "x" of "y"
- Array.prototype.concat()
- Array.prototype.find()
- Array.prototype.flat()
- Array.prototype.flatMap()
- Array.prototype.includes()
- Array.prototype.indexOf()
- Array.prototype.map()
- Date.prototype.setHours()
- Date.prototype.toString()
- Date.prototype.toUTCString()
- Error
- Function.prototype.call()
- Generator
- Intl.DateTimeFormat
- JSON.stringify()
- Map
- Math.hypot()
- Math.round()
- Object.getOwnPropertyNames()
- Object.prototype.constructor
- Promise.prototype.finally()
- Promise.prototype.then()
- Promise.race()
- Promise.resolve()
- handler.apply()
- RegExp
- Set
- Set.prototype.forEach()
- Set.prototype.values()
- String.prototype.concat()
- WeakMap
- WebAssembly.Global
- WebAssembly.Global.prototype
- Statements and declarations
- async function
- block
- break
- for...of
- try...catch
- Strict mode
- JavaScript shells
- Memory Management
- Microsoft JavaScript extensions
- @cc_on
- @if
- @set
- Date.getVarDate
- Debug
- Debug.debuggerEnabled
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackStarting
- Debug.msTraceAsyncOperationStarting
- Debug.msUpdateAsyncCallbackRelation
- Debug.setNonUserCodeExceptions
- Debug.write
- Enumerator
- Enumerator.atEnd
- Enumerator.item
- Enumerator.moveFirst
- Enumerator.moveNext
- Error.description
- Error.number
- Error.stackTraceLimit
- GetObject
- ScriptEngine
- ScriptEngineBuildVersion
- ScriptEngineMajorVersion
- ScriptEngineMinorVersion
- VBArray
- VBArray.dimensions
- VBArray.getItem
- VBArray.lbound
- VBArray.toArray
- VBArray.ubound
- New in JavaScript
Technical reviews
Found 99 pages. Learn more about how to do a technical review.
- JavaScript
- Concurrency model and Event Loop
- Enumerability and ownership of properties
- Details of the object model
- Functions
- Destructuring assignment
- Logical Operators
- Spread syntax
- delete operator
- instanceof
- new operator
- Functions
- getter
- ReferenceError: "x" is not defined
- ReferenceError: reference to undefined property "x"
- SyntaxError: Unexpected token
- TypeError: can't access property "x" of "y"
- Array.isArray()
- Array.prototype.copyWithin()
- Array.prototype.findIndex()
- Array.prototype.flat()
- Array.prototype.flatMap()
- Array.prototype.includes()
- Array.prototype.map()
- Array.prototype.reduce()
- Array.prototype.some()
- Array.prototype[@@iterator]()
- Date.parse()
- Generator
- Generator.prototype.next()
- Intl.NumberFormat
- JSON.stringify()
- Map.prototype
- Map.prototype[@@iterator]()
- Math.round()
- Math.sqrt()
- Object.entries()
- Object.getOwnPropertyDescriptor()
- Object.getOwnPropertyDescriptors()
- Object.keys()
- Promise.all()
- Promise.prototype.finally()
- Promise.prototype.then()
- Promise.reject()
- Promise.resolve()
- RegExp.prototype.exec()
- Set.prototype.forEach()
- String
- String.prototype.concat()
- String.prototype.endsWith()
- String.prototype.includes()
- String.prototype.localeCompare()
- String.prototype.repeat()
- String.prototype.split()
- String.prototype.substr()
- WeakSet
- WebAssembly.Global
- WebAssembly.Global.prototype
- async function
- block
- break
- function*
- Template literals (Template strings)
- Microsoft JavaScript extensions
- @cc_on
- @if
- @set
- ActiveXObject
- Date.getVarDate
- Debug
- Debug.debuggerEnabled
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackCompleted
- Debug.msTraceAsyncCallbackStarting
- Debug.msTraceAsyncOperationStarting
- Debug.msUpdateAsyncCallbackRelation
- Debug.setNonUserCodeExceptions
- Debug.write
- Debug.writeln
- Enumerator
- Enumerator.atEnd
- Enumerator.item
- Enumerator.moveFirst
- Enumerator.moveNext
- Error.description
- Error.number
- Error.stackTraceLimit
- GetObject
- ScriptEngine
- ScriptEngineBuildVersion
- ScriptEngineMajorVersion
- ScriptEngineMinorVersion
- VBArray
- VBArray.dimensions
- VBArray.getItem
- VBArray.lbound
- VBArray.toArray
- VBArray.ubound
- New in JavaScript 1.8.1
Outdated pages
Found 83 pages. These pages haven't been updated in over a year. Outdated pages can have problems with both content and format. Look at these pages and consider: Is this page talking about the Web of today? Does it look consistent with newer pages in this topic area? If not, make any needed changes.
- Differential inheritance in JavaScript
738 days old - Index
703 days old - Deprecated and obsolete features
718 days old - JavaScript error reference
662 days old - ReferenceError: assignment to undeclared variable "x"
526 days old - ReferenceError: invalid assignment left-hand side
845 days old - SyntaxError: missing ] after element list
595 days old - SyntaxError: missing formal parameter
519 days old - SyntaxError: missing name after . operator
543 days old - SyntaxError: missing variable name
557 days old - TypeError: can't access dead object
538 days old - TypeError: can't delete non-configurable array element
459 days old - TypeError: invalid arguments
556 days old - TypeError: variable "x" redeclares argument
595 days old - Warning: -file- is being assigned a //# sourceMappingURL, but already has one
848 days old - Warning: 08/09 is not a legal ECMA-262 octal constant
560 days old - Warning: JavaScript 1.6's for-each-in loops are deprecated
560 days old - Warning: String.x is deprecated; use String.prototype.x instead
563 days old - Warning: expression closures are deprecated
560 days old - Warning: unreachable code after return statement
860 days old - JavaScript properties index
962 days old - Array.of()
381 days old - Array.prototype[@@unscopables]
381 days old - Array.unobserve()
381 days old - Date.prototype.getYear()
386 days old - Date.prototype.setYear()
458 days old - Date.prototype.toGMTString()
458 days old - Error.prototype
370 days old - Error.prototype.message
370 days old - Error.prototype.toString()
370 days old - EvalError.prototype
370 days old - InternalError
370 days old - InternalError.prototype
370 days old - Number.prototype
454 days old - Number.prototype.toSource()
454 days old - Additional examples for Object.defineProperty
418 days old - Object.getNotifier()
370 days old - Object.observe()
370 days old - Object.prototype.__count__
370 days old - Object.prototype.__defineGetter__()
370 days old - Object.prototype.__defineSetter__()
370 days old - Object.prototype.__lookupGetter__()
370 days old - Object.prototype.__lookupSetter__()
370 days old - Object.prototype.__noSuchMethod__
370 days old - Object.prototype.__parent__
370 days old - Object.prototype.eval()
370 days old - Object.unobserve()
370 days old - RangeError.prototype
370 days old - ReferenceError.prototype
370 days old - String.prototype.anchor()
428 days old - String.prototype.big()
454 days old - String.prototype.blink()
454 days old - String.prototype.bold()
454 days old - String.prototype.fixed()
454 days old - String.prototype.fontcolor()
454 days old - String.prototype.fontsize()
454 days old - String.prototype.italics()
413 days old - String.prototype.link()
454 days old - String.prototype.quote()
428 days old - String.prototype.small()
454 days old - String.prototype.strike()
454 days old - String.prototype.sub()
454 days old - String.prototype.sup()
454 days old - String.prototype.toString()
454 days old - String.prototype.valueOf()
454 days old - SyntaxError.prototype
370 days old - TypeError
370 days old - TypeError.prototype
370 days old - URIError
370 days old - URIError.prototype
370 days old - WebAssembly.Instance.prototype
370 days old - WebAssembly.Memory.prototype
370 days old - WebAssembly.Table.prototype
370 days old - Transitioning to strict mode
595 days old - ECMAScript 5 support in Mozilla
624 days old - New in JavaScript 1.1
978 days old - New in JavaScript 1.2
978 days old - New in JavaScript 1.3
978 days old - New in JavaScript 1.4
978 days old - New in JavaScript 1.6
903 days old - New in JavaScript 1.7
552 days old - New in JavaScript 1.8
978 days old - The performance hazards of [[Prototype]] mutation
889 days old
Documentation requests
Found 80 bugs. Documentation request bugs can contain various kinds work related to MDN pages. Read through the bug and ask questions in the bug if in doubt.
| Bug | Summary |
|---|---|
| 1179881 | Write a JS error reference |
| 1201380 | Examples and text don't match up in "details of the object model" page |
| 1204224 | Unclear explanation in "Working With Objects" tutorial |
| 1238394 | Improve Regex docs for capturing groups |
| 1243496 | The function declaration and function expression documentation is incorrect |
| 1245977 | MathML fallback: square root is not displayed correctly |
| 1275816 | Explain how |this| value is calculated in call expression, and the difference between `foo[prop]()` and `func = foo[prop], func()` |
| 1281696 | iterating with let in for-loops |
| 1286628 | Object.prototype.constructor is not a reference to the constructor of the prototype |
| 1294338 | charCodeAt and codePointAt in String documentation seem almost backwards |
| 1301501 | polyfill uses != to check typeof assign to "function" vs !== |
| 1303603 | Clarify that RegExp.prototype.exec() returns a special array |
| 1305261 | Async Functions/Await Documentation |
| 1307755 | Given for..of example needs some explanation, not self-explaining |
| 1309784 | Add Cyclomatic Complexity |
| 1318620 | Slightly misleading example |
| 1318933 | Description of `Object.keys` outdated because it does not return symbol keys |
| 1319979 | Equality comparisons |
| 1322844 | Tagged template literals example does not illustrate point being made |
| 1324194 | Incorrect description for example summary found on array.prototype.filter() page (JSON example) |
| 1325251 | The Math.sign() polyfill contains two type conversions |
| 1334000 | Polyfill example does not detect NaN |
| 1340310 | How does the Cache interface handle cookies? |
| 1343142 | Clarify that Array.prototype.sort() sorts in increasing order |
| 1346500 | The result of the polyfill doesn't meet the result of firefox. |
| 1347496 | Inaccurate information in a code snippet |
| 1352856 | continue statement, example 2. |
| 1357343 | Console.table example does not work as expected |
| 1359860 | Make /W special character regex more clear |
| 1360102 | About the global property with "var" in MDN. |
| 1360661 | Document for Array.from provides a polyfill that cannot create array from a Set |
| 1361299 | mixin replace jQuery.extend with Object.assign |
| 1363684 | tip faster js offsetwith |
| 1365288 | Map.get/set documentation is lacking information |
| 1367757 | Should String.prototype.substr be marked as deprecated? |
| 1371716 | Syntax example provided is incomplete / incorrect |
| 1372019 | Filter the javascript docs on ES version support |
| 1372390 | Promise.all returns already-resolved promises for any combination of non-promises and resolved promises. |
| 1374016 | A consistency issue: different parts of MDN have links where in other parts they're buttons |
| 1376223 | "Promise" Advance Example CodePen Has a Bug |
| 1385876 | Threading coverage on MDN |
| 1389206 | I would like to contribue to progrssive apps section by adding a new sub-article about how to build progressive apps with Angular 2+ |
| 1393872 | Document JavaScript modules |
| 1394123 | Property Accessors: No mention of what happens when a property is not present on an object |
| 1394569 | Array.prototype.filter polyfill compares result of typeof operator to "Function" instead of "function" |
| 1395257 | JS sidebar macros don't interact well with A/B testing framework |
| 1398923 | Migrate static sample code in /samples/domref/dispatch.html to be "live" |
| 1401192 | List support for proper stacktrace in the compat table. |
| 1401753 | Promise, advanced example, code comment incorrect |
| 1405611 | Create a page on property descriptors and flags |
| 1408616 | Re-Introduction to JavaScript - Functions: hiding local variables |
| 1408621 | Re-Introduction to JavaScript - Functions: confusing use of fullName(); |
| 1408998 | More examples in Array.prototype.reduce |
| 1411233 | Document XMLHttpRequestEventTarget.ontimeout |
| 1412101 | Discussion of "boolean operator" should be clarified or deleted |
| 1414088 | Glossary entry for Symbol too detailed; move it into the JavaScript Guide, which doesn't say much |
| 1415201 | Update documentation for missing semicolon. |
| 1419710 | Array.prototype.sort confusing |
| 1424040 | Add glossary entries for weak and strong references; update WeakMap and WeakSet docs to link to them |
| 1433831 | Process described on page doesn't work any more. |
| 1443030 | The expression "execution context" is misleading. |
| 1444255 | Boolean（）中代码运行结果与案例提示不同 |
| 1445988 | Note for IE and Edge including control characters in Intl.DateTimeFormat.format |
| 1447921 | Indexed collections Array class doesn't have static method forEach. prototype does |
| 1456933 | add error page for "allocation size overflow" |
| 1458050 | Promises |
| 1472714 | JS Guide: Asynchronous programming |
| 1474403 | Define "static function" in the Glossary |
| 1476207 | I've written a cheat sheet for Javascript with active links toMDN pages |
| 1476511 | The sourceopen event (MediaSource API) is not documented |
| 1476965 | Document BigInt |
| 1480988 | The syntax explanation for Date.parse doesn't match to the spec |
| 1483152 | Document async iterators and generators |
| 1484772 | MDN: Promise.all() : Information about sync/a-sync resolution possibly irrelevant |
| 1486007 | Add section "Difference between substring() and slice()" |
| 1486312 | Link to SIMD types is non-existent |
| 1487930 | Language Feedback directly in Mozilla |
| 1490246 | Iterator example |
| 1491693 | Dead link on JS typeof page |
| 1492709 | Broken "Arguments" link in "for...of" page |
Browse as bug list.
Localizations
Please help us to localize this documentation into different languages. Read more about how to translate.
| Language | Pages | Translated | Translations up to date |
|---|---|---|---|
| af | 923 | 0 (0%) | 0 (0%) |
| bn-BD | 923 | 36 (3%) | 4 (11%) |
| ca | 923 | 321 (34%) | 57 (17%) |
| de | 923 | 571 (61%) | 442 (77%) |
| es | 923 | 445 (48%) | 118 (26%) |
| fa | 923 | 23 (2%) | 2 (8%) |
| fr | 862 | 857 (99%) | 685 (79%) |
| id | 923 | 107 (11%) | 5 (4%) |
| it | 923 | 159 (17%) | 20 (12%) |
| ja | 862 | 807 (93%) | 250 (30%) |
| kab | 923 | 2 (0%) | 0 (0%) |
| ko | 860 | 442 (51%) | 121 (27%) |
| nl | 923 | 70 (7%) | 10 (14%) |
| pl | 923 | 316 (34%) | 33 (10%) |
| pt-BR | 923 | 399 (43%) | 80 (20%) |
| pt-PT | 923 | 61 (6%) | 6 (9%) |
| ro | 923 | 34 (3%) | 3 (8%) |
| ru | 862 | 611 (70%) | 113 (18%) |
| uk | 923 | 184 (19%) | 83 (45%) |
| zh-CN | 862 | 777 (90%) | 296 (38%) |
Structure of the MDN JavaScript docs
| # | Chapter | Pages | Priority | Notes |
|---|---|---|---|---|
| 0 | Value & function properties in the global scope | 16 | 1 | Complete. |
| 1 | Object | 40 | 1 |
Complete. |
| 2 | Function | 14 | 1 | Complete. |
| 3 | Array | 38 | 1 | Complete. |
| 4 | String | 50 | 1 | Complete. |
| 5 | Boolean | 5 | 1 | Complete. |
| 6 | Number | 24 | 1 |
Complete. |
| 7 | Math | 44 | 1 | Complete. |
| 8 | Date | 53 | 1 | Complete. |
| 9 | RegExp | 21 | 1 | Complete. |
| 10 |
Error |
24 | 4 | Complete. |
| 11 | JSON | 3 | 1 | Complete. |
| 12 | Intl Intl.Collator Intl.DateTimeFormat Intl.NumberFormat |
16 | 2 | Complete. |
| 13 | Map | 13 | 2 | Complete. |
| 14 | WeakMap | 7 | 2 | Complete. |
| 15 | Set | 11 | 2 | Complete. |
| 16 | WeakSet | 6 | 2 | Complete. |
| 17 | Proxy | 17 | 3 | Complete. |
| 18 | Reflect | 15 | 3 | Complete. |
| 19 | Generator (legacy and ES2015) Iterator StopIteration GeneratorFunction |
8 | 2 | Complete. |
| 20 | ArrayBuffer (6)DataView (21)TypedArray (34 [+ 3])Float32ArrayFloat64ArrayInt16ArrayInt32ArrayInt8ArrayUint16ArrayUint32ArrayUint8ArrayUint8ClampedArray |
73 | 2 | Missing pages:
|
| 21 | Promise | 8 | 1 | Complete. |
| 22 | Symbol | 9 | 2 |
Missing pages:
|
| 23 | ParallelArray | 1 | 5 | Complete. |
| 24 | Atomics SharedArrayBuffer |
17 | 4 | Preffed off. Spec in flux. |
| 25 | Expressions & Operators | 29 | 1 | Complete. |
| 26 | Statements & Declarations | 27 | 1 | Complete. |
| 27 | Functions | 11 | 1 |
Complete. |
| 28 | Classes | 4 | 1 | Complete. |
| 29 | JavaScript Guide | 15 | 1 |
|
| 30 | New in JavaScript | 15 | 4 |
Complete. |
| 31 | JavaScript error reference | 36 | 3 | Explains error messages (v8, Chakra). So those people searching for errors will find guidance. |
| 32 | Articles/Tutorials/Misc | 17 |
3 |
|
| 33 | Meta pages | 9 | 4 |
Other tasks to do
- Go through Firefox release notes for developers and site compat notes and make sure JS changes are documented properly in the references.
- Make sure our compat tables are up to date by also going through bug trackers of other open source browsers (e.g. WebKit, Blink)
- Write a changelog for Chrome JavaScript releases like we have for Firefox. Same for other browsers/node.js?
- Meta article about how to document in the JS MDN area.
- Write more JavaScript error documentation: The list of errors which have no mdn pages link corresponds to SpiderMonkey error code which are reported to the devtool console which do not have any corresponding MDN pages.
Tagging standard
- Pages in the JavaScript/ page tree should at least have the tag "JavaScript".
- For methods belonging to an object, the name of the Object should be added (e.g.
String.fromCharCodeshould have "String"). - Methods should have "Method" and properties need a "Property" tag. All prototype members have the "prototype" tag.
- Features added in a new ECMAScript version have the tags "ECMAScript6" and "ECMAScript 2015" or later versions/years.
- The Experimental tag should only be used with new features where the standard in not yet finalized (e.g. in a strawman proposal) and the feature is in a Nightly version or behind a preference.
- Features are Deprecated if their usage is discouraged and are Obsolete if they have been removed from engines.
- If pages need any type of work, a "Needs*" tag should be added (see above).
Specifications
The following specifications are taken under consideration for this project:
| Specification | Status |
|---|---|
| ECMAScript 1st Edition (ECMA-262) | Standard |
| ECMAScript 3rd Edition (ECMA-262) | Standard |
| ECMAScript 5.1 (ECMA-262) | Standard |
| ECMAScript 2015 (6th Edition, ECMA-262) | Standard |
| ECMAScript 2016 (ECMA-262) | Standard |
| ECMAScript 2017 (ECMA-262) | Standard |
| ECMAScript 2018 (ECMA-262) | Standard |
| ECMAScript Latest Draft (ECMA-262) | Draft |
| ECMAScript Internationalization API 1.0 (ECMA-402) | Standard |
| ECMAScript Internationalization API 2.0 (ECMA-402) | Standard |
| ECMAScript Internationalization API 4.0 (ECMA-402) | Draft |
| ECMAScript Proposals (with advanced stage and at least 1 implementation) | Draft |
Help the 'JavaScript' documentation project…
Topic driver : Florian Scholz (IRC nickname: fscholz)
Look at the current status of the 'JavaScript' documentation.
Don't hesitate to contact us on #mdn or on the MDN discourse group/list:
Document Tags and Contributors
Tags:
Contributors to this page:
ExE-Boss,
fscholz,
wbamberg,
kdex,
nbp,
SphinxKnight,
manjumg23,
indocomtrade,
apurv-pandey,
ariesrtheones1369,
jswisher,
Havvy,
Sheppy
Last updated by:
ExE-Boss,