How do I encode a JavaScript object as JSON?

Question

Is there a good way to encode a JavaScript object as JSON?

I have a list of key value pairs...where the name is from a checkbox, and the value is either true or false based on whether the box is checked or not:

var values = {};
$('#checks :checkbox').each(function() { values[this.name]=this.checked; }); 

I want to pass these values into a JSON object so store into a cookie to render a table (Columns will be added according to what the user checks off).

Does anyone know a solution?

• Adam Rackis: There's no such thing as a json object. Are you trying to serialize values into json, or are you trying to pass values into a JavaScript object?
• daniel langer: I want to be able to create a json file to store the values of the checkboxes so the users choices are saved in a cookie. I am new to json so I don't know whicH i want
• Bergi: possible duplicate of storing and retrieving json objects to / from a cookie, serialize form to json and store in the cookie and How do I store this JSON object as a cookie and than read it in vanilla javascript?
• Ritsaert Hornstra: IE7 and below need the JSON2.js library and do not support this API natively. caniuse.com/json

Answer 1

I think you can use JSON.stringify:

// after your each loop
JSON.stringify(values);

• daniel langer: I put this in an alert() but nothing appears
• Adam Rackis: @daniellanger - based on your comment, this is the answer. You'll need to do some debugging to see why things aren't showing up
• daniel langer: so how can I save this to a file/ store it as a cookie?
• Matthew Lock: IE 10 is giving: JavaScript runtime error: 'JSON' is undefined
• Boaz: The native JSON methods are supported by IE8 and above. That being said, in IE they are only available in Standards Mode.

Answer 2

All major browsers now include native JSON encoding/decoding.

// To encode an object (This produces a string)
var json_str = JSON.stringify(myobject); 
// To decode (This produces an object)
var obj = JSON.parse(json_str);

Note that only valid JSON data will be encoded. For example:

var obj = {'foo': 1, 'bar': (function (x) { return x; })}
JSON.stringify(obj) // --> "{\"foo\":1}"

Valid JSON types are: objects, strings, numbers, arrays, true, false, and null.

Some JSON resources:

• JSON on Mozilla Developer Network
• JSON on Wikipedia

• vezult: Well, they are called "objects" in javascript. But yes, boolean values can be represented in JSON.