Referência de JavaScript

Esta parte da secção de JavaScript na MDN serve como um repositório de factos sobre a linguage JavaScript. Leia mais sobre esta referência.

Objetos Globais

Este capítulo documenta todos os objetos integrados, juntamente com os seus respetivos métodos e propriedades.

Comunicados

Este capítulo documenta todos os extratos e declarações de JavaScript.

Expressões e operadores

Este capítulo documenta todas as expressões e operadores de JavaScript.

Funções

Este capítulo documenta como trabalhar com funções JavaScript para desenvolver aplicações para a Web.

Páginas de referência adicionais

Tópicos relacionados
  1. JavaScript
  2. Tutorials:
  3. Complete beginners
    1. JavaScript basics
    2. JavaScript first steps
    3. JavaScript building blocks
    4. Introducing JavaScript objects
  4. JavaScript Guide
    1. Introduction
    2. Grammar and types
    3. Control flow and error handling
    4. Loops and iteration
    5. Functions
    6. Expressions and operators
    7. Numbers and dates
    8. Text formatting
    9. Regular expressions
    10. Indexed collections
    11. Keyed collections
    12. Working with objects
    13. Details of the object model
    14. Using promises
    15. Iterators and generators
    16. Meta programming
  5. Intermediate
    1. Introducing JavaScript objects
    2. Client-side web APIs
    3. A re-introduction to JavaScript
    4. JavaScript data structures
    5. Equality comparisons and sameness
    6. Closures
  6. Advanced
    1. Inheritance and the prototype chain
    2. Strict mode
    3. JavaScript typed arrays
    4. Memory Management
    5. Concurrency model and Event Loop
  7. References:
  8. Built-in objects
    1. Array
    2. ArrayBuffer
    3. AsyncFunction [Translate]
    4. Atomics [Translate]
    5. BigInt [Translate]
    6. Booliano
    7. DataView [Translate]
    8. Date [Translate]
    9. Error [Translate]
    10. EvalError [Translate]
    11. Float32Array [Translate]
    12. Float64Array [Translate]
    13. Function
    14. Generator [Translate]
    15. GeneratorFunction [Translate]
    16. Infinity [Translate]
    17. Int16Array [Translate]
    18. Int32Array [Translate]
    19. Int8Array [Translate]
    20. InternalError [Translate]
    21. Intl [Translate]
    22. Intl.Collator [Translate]
    23. Intl.DateTimeFormat [Translate]
    24. Intl.ListFormat [Translate]
    25. Intl.NumberFormat [Translate]
    26. Intl.PluralRules [Translate]
    27. Intl.RelativeTimeFormat [Translate]
    28. JSON [Translate]
    29. Map [Translate]
    30. Math
    31. NaN [Translate]
    32. Number
    33. Object
    34. Promise [Translate]
    35. Proxy [Translate]
    36. RangeError [Translate]
    37. ReferenceError [Translate]
    38. Reflect [Translate]
    39. RegExp [Translate]
    40. Set [Translate]
    41. SharedArrayBuffer [Translate]
    42. String
    43. Symbol
    44. SyntaxError [Translate]
    45. TypeError [Translate]
    46. TypedArray [Translate]
    47. URIError [Translate]
    48. Uint16Array [Translate]
    49. Uint32Array [Translate]
    50. Uint8Array [Translate]
    51. Uint8ClampedArray [Translate]
    52. WeakMap [Translate]
    53. WeakSet [Translate]
    54. WebAssembly [Translate]
    55. decodeURI() [Translate]
    56. decodeURIComponent() [Translate]
    57. encodeURI()
    58. encodeURIComponent() [Translate]
    59. escape() [Translate]
    60. eval() [Translate]
    61. isFinite() [Translate]
    62. isNaN() [Translate]
    63. null [Translate]
    64. parseFloat() [Translate]
    65. parseInt() [Translate]
    66. undefined [Translate]
    67. unescape() [Translate]
    68. uneval() [Translate]
  9. Expressions & operators
    1. Arithmetic operators [Translate]
    2. Array comprehensions [Translate]
    3. Assignment operators [Translate]
    4. Bitwise operators [Translate]
    5. Comma operator [Translate]
    6. Comparison operators [Translate]
    7. Conditional (ternary) operator [Translate]
    8. Destructuring assignment [Translate]
    9. Expression closures [Translate]
    10. Generator comprehensions [Translate]
    11. Grouping operator [Translate]
    12. Legacy generator function expression [Translate]
    13. Logical operators [Translate]
    14. Inicializador de objeto
    15. Precedência de operador
    16. Pipeline operator [Translate]
    17. Property accessors [Translate]
    18. Spread syntax [Translate]
    19. async function expression [Translate]
    20. await [Translate]
    21. class expression [Translate]
    22. delete operator [Translate]
    23. function expression [Translate]
    24. function* expression [Translate]
    25. in operator [Translate]
    26. instanceof [Translate]
    27. new operator [Translate]
    28. new.target [Translate]
    29. super [Translate]
    30. this
    31. typeof [Translate]
    32. void operator [Translate]
    33. yield [Translate]
    34. yield* [Translate]
  10. Statements & declarations
    1. Legacy generator function [Translate]
    2. async function [Translate]
    3. block
    4. break [Translate]
    5. class [Translate]
    6. const [Translate]
    7. continue [Translate]
    8. debugger [Translate]
    9. default [Translate]
    10. do...while [Translate]
    11. empty [Translate]
    12. export [Translate]
    13. for
    14. for await...of [Translate]
    15. for each...in [Translate]
    16. for...in [Translate]
    17. for...of [Translate]
    18. function declaration [Translate]
    19. function* [Translate]
    20. if...else
    21. import [Translate]
    22. import.meta [Translate]
    23. label [Translate]
    24. let [Translate]
    25. return
    26. switch [Translate]
    27. throw
    28. try...catch
    29. var [Translate]
    30. while [Translate]
    31. with [Translate]
  11. Functions
    1. Funções de arrow
    2. Default parameters [Translate]
    3. Method definitions [Translate]
    4. Rest parameters [Translate]
    5. O objeto arguments
    6. getter [Translate]
    7. setter [Translate]
  12. Classes
    1. constructor [Translate]
    2. extends [Translate]
    3. static
  13. Errors
    1. Error: Permission denied to access property "x" [Translate]
    2. InternalError: too much recursion [Translate]
    3. RangeError: argument is not a valid code point [Translate]
    4. RangeError: invalid array length [Translate]
    5. RangeError: invalid date [Translate]
    6. RangeError: precision is out of range [Translate]
    7. RangeError: radix must be an integer [Translate]
    8. RangeError: repeat count must be less than infinity [Translate]
    9. RangeError: repeat count must be non-negative [Translate]
    10. ReferenceError: "x" is not defined [Translate]
    11. ReferenceError: assignment to undeclared variable "x" [Translate]
    12. ReferenceError: can't access lexical declaration`X' before initialization [Translate]
    13. ReferenceError: deprecated caller or arguments usage [Translate]
    14. ReferenceError: invalid assignment left-hand side [Translate]
    15. ReferenceError: reference to undefined property "x" [Translate]
    16. SyntaxError: "0"-prefixed octal literals and octal escape seq. are deprecated [Translate]
    17. SyntaxError: "use strict" not allowed in function with non-simple parameters [Translate]
    18. SyntaxError: "x" is a reserved identifier [Translate]
    19. SyntaxError: JSON.parse: bad parsing [Translate]
    20. SyntaxError: Malformed formal parameter [Translate]
    21. SyntaxError: Unexpected token
    22. SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead [Translate]
    23. SyntaxError: a declaration in the head of a for-of loop can't have an initializer [Translate]
    24. SyntaxError: applying the 'delete' operator to an unqualified name is deprecated [Translate]
    25. SyntaxError: for-in loop head declarations may not have initializers [Translate]
    26. Erro de sintaxe: declaração de função precisa de um nome
    27. SyntaxError: identifier starts immediately after numeric literal [Translate]
    28. SyntaxError: illegal character [Translate]
    29. SyntaxError: invalid regular expression flag "x" [Translate]
    30. SyntaxError: missing ) after argument list [Translate]
    31. SyntaxError: missing ) after condition [Translate]
    32. SyntaxError: missing : after property id [Translate]
    33. SyntaxError: missing ; before statement [Translate]
    34. SyntaxError: missing = in const declaration [Translate]
    35. SyntaxError: missing ] after element list [Translate]
    36. SyntaxError: missing formal parameter [Translate]
    37. SyntaxError: missing name after . operator [Translate]
    38. SyntaxError: missing variable name [Translate]
    39. SyntaxError: missing } after function body [Translate]
    40. SyntaxError: missing } after property list [Translate]
    41. SyntaxError: redeclaration of formal parameter "x" [Translate]
    42. SyntaxError: return not in function [Translate]
    43. SyntaxError: test for equality (==) mistyped as assignment (=)? [Translate]
    44. SyntaxError: unterminated string literal [Translate]
    45. TypeError: "x" has no properties [Translate]
    46. TypeError: "x" is (not) "y" [Translate]
    47. TypeError: "x" is not a constructor [Translate]
    48. TypeError: "x" is not a function [Translate]
    49. TypeError: "x" is not a non-null object [Translate]
    50. TypeError: "x" is read-only [Translate]
    51. TypeError: 'x' is not iterable [Translate]
    52. TypeError: More arguments needed [Translate]
    53. TypeError: Reduce of empty array with no initial value [Translate]
    54. TypeError: can't access dead object [Translate]
    55. TypeError: can't access property "x" of "y" [Translate]
    56. TypeError: can't define property "x": "obj" is not extensible [Translate]
    57. TypeError: can't delete non-configurable array element [Translate]
    58. TypeError: can't redefine non-configurable property "x" [Translate]
    59. TypeError: cannot use 'in' operator to search for 'x' in 'y' [Translate]
    60. TypeError: cyclic object value [Translate]
    61. TypeError: invalid 'instanceof' operand 'x' [Translate]
    62. TypeError: invalid Array.prototype.sort argument [Translate]
    63. TypeError: invalid arguments [Translate]
    64. TypeError: invalid assignment to const "x" [Translate]
    65. TypeError: property "x" is non-configurable and can't be deleted [Translate]
    66. TypeError: setting getter-only property "x" [Translate]
    67. TypeError: variable "x" redeclares argument [Translate]
    68. URIError: malformed URI sequence [Translate]
    69. Warning: -file- is being assigned a //# sourceMappingURL, but already has one [Translate]
    70. Warning: 08/09 is not a legal ECMA-262 octal constant [Translate]
    71. Warning: Date.prototype.toLocaleFormat is deprecated [Translate]
    72. Warning: JavaScript 1.6's for-each-in loops are deprecated [Translate]
    73. Warning: String.x is deprecated; use String.prototype.x instead [Translate]
    74. Warning: expression closures are deprecated [Translate]
    75. Aviso: código inacessível depois de declaração de retorno
    76. X.prototype.y called on incompatible type [Translate]
  14. Misc
    1. JavaScript technologies overview
    2. Lexical grammar
    3. JavaScript data structures
    4. Enumerability and ownership of properties
    5. Iteration protocols
    6. Strict mode
    7. Transitioning to strict mode
    8. Template literals
    9. Deprecated features
  15. New in JavaScript
    1. ECMAScript 2015 support in Mozilla [Translate]
    2. ECMAScript 5 support in Mozilla [Translate]
    3. ECMAScript Next support in Mozilla [Translate]
    4. Firefox JavaScript changelog [Translate]
    5. New in JavaScript 1.1 [Translate]
    6. New in JavaScript 1.2 [Translate]
    7. New in JavaScript 1.3 [Translate]
    8. New in JavaScript 1.4 [Translate]
    9. New in JavaScript 1.5 [Translate]
    10. New in JavaScript 1.6 [Translate]
    11. New in JavaScript 1.7 [Translate]
    12. Novidades no Javascript 1.8
    13. New in JavaScript 1.8.1 [Translate]
    14. New in JavaScript 1.8.5 [Translate]
  16. Documentation:
  17. Useful lists
    1. All pages index
    2. Methods index
    3. Properties index
    4. Pages tagged "JavaScript"
  18. Contribute
    1. JavaScript doc status
    2. The MDN project