AJAX - The Complete Reference

Chapter 4: Data Formats 123

PART I

because the associated character such as left and right brackets and the comma ( [ , ] ) are

safely found in URLs. For example, given a JavaScript array like so:

var pets = ['Angus Powell', 'Rufus', 'Tucker O\' Reilly'];

to be sent to a server program handle.php, you might form a URL like:

http://ajaxref.com/pet-tracker.php?pets[]=Angus+Powell&pets[]=Rufus&pets=[]

Tucker+O%27Reilly

Now, you might wonder how to encode a JavaScript object value like the following into

the URL format:

var dog = {name: "Angus",

breed: "Scotty",

age: 5}

In JavaScript, objects and arrays are pretty much interchangeable, so the previous object can

be alternatively written as an associative array like so:

dog[name] = "Angus Powell";

dog["breed"] = "Scotty";

dog["age"] = 5;

Given that form, it can be encoded into a standard x-www-form-urlencoded payload

like so:

http://ajaxref.com/pet-tracker.php?dog[name]=Angus+Powell&dog[breed]=Scotty

&dog[age]=5

We present a basic encodeObject() function here that will encode a passed array or

object into a URL safe form. It relies on the previously defined encodeValue() function to

perform the correct value encoding.

function encodeObject(obj, indexString)

{

var queryString = "";

if(typeof(obj) == "object")

{

for(keyStr in obj)

{

var key = keyStr;

var val = obj[key];

if (indexString)

{

if (!obj.length)

key = indexString + "[" + encodeValue(key) + "]";

else

key = indexString + "[]";

}

if (typeof(val) == "object")

queryString += encodeObject(val, key);