1# JSON 3 #
  2
  3![JSON 3 Logo](http://bestiejs.github.io/json3/page/logo.png)
  4
  5**JSON 3** is a modern JSON implementation compatible with a variety of JavaScript platforms, including Internet Explorer 6, Opera 7, Safari 2, and Netscape 6. The current version is **3.2.6**.
  6
  7- [Development Version](https://raw.github.com/bestiejs/json3/v3.2.6/lib/json3.js) *(40 KB; uncompressed with comments)*
  8- [Production Version](https://raw.github.com/bestiejs/json3/v3.2.6/lib/json3.min.js) *(3.3 KB; compressed and `gzip`-ped)*
  9
 10CDN copies are also available at [cdnjs](http://cdnjs.com/libraries/json3/) & [jsDelivr](http://www.jsdelivr.com/#!json3).
 11
 12[JSON](http://json.org/) is a language-independent data interchange format based on a loose subset of the JavaScript grammar. Originally popularized by [Douglas Crockford](http://www.crockford.com/), the format was standardized in the [fifth edition](http://es5.github.com/) of the ECMAScript specification. The 5.1 edition, ratified in June 2011, incorporates several modifications to the grammar pertaining to the serialization of dates.
 13
 14JSON 3 exposes two functions: `stringify()` for [serializing](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/JSON/stringify) a JavaScript value to JSON, and `parse()` for [producing](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/JSON/parse) a JavaScript value from a JSON source string. It is a **drop-in replacement** for [JSON 2](http://json.org/js). The functions behave exactly as described in the ECMAScript spec, **except** for the date serialization discrepancy noted below.
 15
 16The JSON 3 parser does **not** use `eval` or regular expressions. This provides security and performance benefits in obsolete and mobile environments, where the margin is particularly significant. The complete [benchmark suite](http://jsperf.com/json3) is available on [jsPerf](http://jsperf.com/).
 17
 18The project is [hosted on GitHub](http://git.io/json3), along with the [unit tests](http://bestiejs.github.io/json3/test/test_browser.html). It is part of the [BestieJS](https://github.com/bestiejs) family, a collection of best-in-class JavaScript libraries that promote cross-platform support, specification precedents, unit testing, and plenty of documentation.
 19
 20# Changes from JSON 2 #
 21
 22JSON 3...
 23
 24* Correctly serializes primitive wrapper objects.
 25* Throws a `TypeError` when serializing cyclic structures (JSON 2 recurses until the call stack overflows).
 26* Utilizes **feature tests** to detect broken or incomplete *native* JSON implementations (JSON 2 only checks for the presence of the native functions). The tests are only executed once at runtime, so there is no additional performance cost when parsing or serializing values.
 27
 28**As of v3.2.3**, JSON 3 is compatible with [Prototype](http://prototypejs.org) 1.6.1 and older.
 29
 30In contrast to JSON 2, JSON 3 **does not**...
 31
 32* Add `toJSON()` methods to the `Boolean`, `Number`, and `String` prototypes. These are not part of any standard, and are made redundant by the design of the `stringify()` implementation.
 33* Add `toJSON()` or `toISOString()` methods to `Date.prototype`. See the note about date serialization below.
 34
 35## Date Serialization
 36
 37**JSON 3 deviates from the specification in one important way**: it does not define `Date#toISOString()` or `Date#toJSON()`. This preserves CommonJS compatibility and avoids polluting native prototypes. Instead, date serialization is performed internally by the `stringify()` implementation: if a date object does not define a custom `toJSON()` method, it is serialized as a [simplified ISO 8601 date-time string](http://es5.github.com/#x15.9.1.15).
 38
 39**Several native `Date#toJSON()` implementations produce date time strings that do *not* conform to the grammar outlined in the spec**. For instance, all versions of Safari 4, as well as JSON 2, fail to serialize extended years correctly. Furthermore, JSON 2 and older implementations omit the milliseconds from the date-time string (optional in ES 5, but required in 5.1). Finally, in all versions of Safari 4 and 5, serializing an invalid date will produce the string `"Invalid Date"`, rather than `null`. Because these environments exhibit other serialization bugs, however, JSON 3 will override the native `stringify()` implementation.
 40
 41Portions of the date serialization code are adapted from the [`date-shim`](https://github.com/Yaffle/date-shim) project.
 42
 43# Usage #
 44
 45## Web Browsers
 46
 47    <script src="http://bestiejs.github.io/json3/lib/json3.js"></script>
 48    <script>
 49      JSON.stringify({"Hello": 123});
 50      // => '{"Hello":123}'
 51      JSON.parse("[[1, 2, 3], 1, 2, 3, 4]", function (key, value) {
 52        if (typeof value == "number") {
 53          value = value % 2 ? "Odd" : "Even";
 54        }
 55        return value;
 56      });
 57      // => [["Odd", "Even", "Odd"], "Odd", "Even", "Odd", "Even"]
 58    </script>
 59
 60## CommonJS Environments
 61
 62    var JSON3 = require("./path/to/json3");
 63    JSON3.parse("[1, 2, 3]");
 64    // => [1, 2, 3]
 65
 66## JavaScript Engines
 67
 68    load("path/to/json3.js");
 69    JSON.stringify({"Hello": 123, "Good-bye": 456}, ["Hello"], "\t");
 70    // => '{\n\t"Hello": 123\n}'
 71
 72# Compatibility #
 73
 74JSON 3 has been **tested** with the following web browsers, CommonJS environments, and JavaScript engines.
 75
 76## Web Browsers
 77
 78- Windows [Internet Explorer](http://www.microsoft.com/windows/internet-explorer), version 6.0 and higher
 79- Mozilla [Firefox](http://www.mozilla.com/firefox), version 1.0 and higher
 80- Apple [Safari](http://www.apple.com/safari), version 2.0 and higher
 81- [Opera](http://www.opera.com) 7.02 and higher
 82- [Mozilla](http://sillydog.org/narchive/gecko.php) 1.0, [Netscape](http://sillydog.org/narchive/) 6.2.3, and [SeaMonkey](http://www.seamonkey-project.org/) 1.0 and higher
 83
 84## CommonJS Environments
 85
 86- [Node](http://nodejs.org/) 0.2.6 and higher
 87- [RingoJS](http://ringojs.org/) 0.4 and higher
 88- [Narwhal](http://narwhaljs.org/) 0.3.2 and higher
 89
 90## JavaScript Engines
 91
 92- Mozilla [Rhino](http://www.mozilla.org/rhino) 1.5R5 and higher
 93- WebKit [JSC](https://trac.webkit.org/wiki/JSC)
 94- Google [V8](http://code.google.com/p/v8)
 95
 96## Known Incompatibilities
 97
 98* Attempting to serialize the `arguments` object may produce inconsistent results across environments due to specification version differences. As a workaround, please convert the `arguments` object to an array first: `JSON.stringify([].slice.call(arguments, 0))`.
 99
100## Required Native Methods
101
102JSON 3 assumes that the following methods exist and function as described in the ECMAScript specification:
103
104- The `Number`, `String`, `Array`, `Object`, `Date`, `SyntaxError`, and `TypeError` constructors.
105- `String.fromCharCode`
106- `Object#toString`
107- `Function#call`
108- `Math.floor`
109- `Number#toString`
110- `Date#valueOf`
111- `String.prototype`: `indexOf`, `charCodeAt`, `charAt`, `slice`.
112- `Array.prototype`: `push`, `pop`, `join`.
113
114# Contribute #
115
116Check out a working copy of the JSON 3 source code with [Git](http://git-scm.com/):
117
118    $ git clone git://github.com/bestiejs/json3.git
119    $ cd json3
120    $ git submodule update --init
121
122If you'd like to contribute a feature or bug fix, you can [fork](http://help.github.com/fork-a-repo/) JSON 3, commit your changes, and [send a pull request](http://help.github.com/send-pull-requests/). Please make sure to update the unit tests in the `test` directory as well.
123
124Alternatively, you can use the [GitHub issue tracker](https://github.com/bestiejs/json3/issues) to submit bug reports, feature requests, and questions, or send tweets to [@kitcambridge](http://twitter.com/kitcambridge).
125
126JSON 3 is released under the [MIT License](http://kit.mit-license.org/).