JSON

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This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

* Some parts of this feature may have varying levels of support.

JSON 物件包含了解析、或是轉換為 JavaScript Object Notation（JSON）格式的方法。這物件不能被呼叫或建構；而除了它的兩個方法屬性以外，本身也沒有特別的功能。

描述

JavaScript Object Notation

JSON 是序列物件、陣列、數字、字串、布林值、還有 null 的語法。它建基、但不同於 JavaScript：有些 JavaScript 不是 JSON、而有些 JSON 不是 JavaScript。請參見 JSON: The JavaScript subset that isn't。

JavaScript 型別	與 JSON 的差別
物件與陣列	屬性名稱必須是包含在雙引號中的字串；禁止尾後逗號。
數字	數字不可以 0 作為開頭；小數點前面必須至少有一位數字；不支援 `NaN` 和 `Infinity`。

JSON 的完整語法

JSON-text = object / array
begin-array     = ws %x5B ws  ; [ left square bracket
begin-object    = ws %x7B ws  ; { left curly bracket
end-array       = ws %x5D ws  ; ] right square bracket
end-object      = ws %x7D ws  ; } right curly bracket
name-separator  = ws %x3A ws  ; : colon
value-separator = ws %x2C ws  ; , comma
ws = *(
     %x20 /              ; Space
     %x09 /              ; Horizontal tab
     %x0A /              ; Line feed or New line
     %x0D                ; Carriage return
     )
value = false / null / true / object / array / number / string
false = %x66.61.6c.73.65   ; false
null  = %x6e.75.6c.6c      ; null
true  = %x74.72.75.65      ; true
object = begin-object [ member *( value-separator member ) ]
         end-object
member = string name-separator value
array = begin-array [ value *( value-separator value ) ] end-array
number = [ minus ] int [ frac ] [ exp ]
decimal-point = %x2E       ; .
digit1-9 = %x31-39         ; 1-9
e = %x65 / %x45            ; e E
exp = e [ minus / plus ] 1*DIGIT
frac = decimal-point 1*DIGIT
int = zero / ( digit1-9 *DIGIT )
minus = %x2D               ; -
plus = %x2B                ; +
zero = %x30                ; 0
string = quotation-mark *char quotation-mark
char = unescaped /
    escape (
        %x22 /          ; "    quotation mark  U+0022
        %x5C /          ; \    reverse solidus U+005C
        %x2F /          ; /    solidus         U+002F
        %x62 /          ; b    backspace       U+0008
        %x66 /          ; f    form feed       U+000C
        %x6E /          ; n    line feed       U+000A
        %x72 /          ; r    carriage return U+000D
        %x74 /          ; t    tab             U+0009
        %x75 4HEXDIG )  ; uXXXX                U+XXXX
escape = %x5C              ; \
quotation-mark = %x22      ; "
unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
HEXDIG = DIGIT / %x41-46 / %x61-66   ; 0-9, A-F, or a-f
       ; HEXDIG equivalent to HEXDIG rule in [RFC5234]
DIGIT = %x30-39            ; 0-9
      ; DIGIT equivalent to DIGIT rule in [RFC5234]

Insignificant whitespace may be present anywhere except within a JSONNumber (numbers must contain no whitespace) or JSONString (where it is interpreted as the corresponding character in the string, or would cause an error). The tab character (U+0009), carriage return (U+000D), line feed (U+000A), and space (U+0020) characters are the only valid whitespace characters.

方法

JSON.parse(): 解析 JSON 字串，能改變給定值和屬性、接著回傳解析值。
JSON.stringify(): 回傳給定的 JSON 對應字串，可自行決定只想包括哪些特定屬性、或替換的屬性值。

規範

Specification
ECMAScript Language Specification # sec-json-object

瀏覽器相容性

BCD tables only load in the browser

參見

Date.prototype.toJSON()