JQuery + Json - first steps with an example - php

Question

I need (recently) to get an array from the server after an ajax call created by jquery. I know that i can do it using JSON. But i don't know how to implement it with JQuery (im new with JSON). I try to search in internet some example, but i didnt find it.
This is the code :
// js-jquery function
function changeSponsor() {
$.ajax({
type: 'POST',
cache: false,
url: './auth/ajax.php',
data: 'id=changespon',
success: function(msg) {
// here i need to manage the JSON object i think
}
});
return false;
}
// php-server function
if((isset($_POST['id'])) && ($_POST['id']=="changespon")) {
$linkspon[0]="my ";
$linkspon[1]="name ";
$linkspon[2]="is ";
$linkspon[3]="marco!";
echo $linkspon;
}
in fact, i need to get the array $linkspon after the ajax call and manage it. How can do it? I hope this question is clear. Thanks
EDIT
ok. this is now my jquery function. I add the $.getJSON function, but i think in a wrong place :)
function changeSponsor() {
$.ajax({
type: 'POST',
cache: false,
url: './auth/ajax.php',
data: 'id=changespon',
dataType: 'json',
success: function(data) {
$.getJSON(url, function(data) { alert(data[0]) } );
}
});
return false;
}

Answer 1

Two things you need to do.
You need to convert your array to JSON before outputting it in PHP. This can easily be done using json_encode, assuming you have a recent version of PHP (5.2+). It also is best practice for JSON to use named key/value pairs, rather than a numeric index.
In your jQuery .ajax call, set dataType to 'json' so it know what type of data to expect.
// JS/jQuery
function changeSponsor() {
$.ajax({
type: 'POST',
cache: false,
url: './auth/ajax.php',
data: 'id=changespon',
dataType: 'json',
success: function(data) {
console.log(data.key); // Outputs "value"
console.log(data.key2); // Outputs "value2"
}
});
return false;
}
// PHP
if((isset($_POST['id'])) && ($_POST['id']=="changespon")) {
$linkspon["key"]= "value";
$linkspon["key2"]= "value2";
echo json_encode($linkspon);
}

Answer 2

1) PHP: You need to use json_encode on your array.
e.g.
// php-server function
if((isset($_POST['id'])) && ($_POST['id']=="changespon")) {
$linkspon[0]="my ";
$linkspon[1]="name ";
$linkspon[2]="is ";
$linkspon[3]="marco!";
echo json_encode($linkspon);
}
2) JQUERY:
use $.getJSON(url, function(data) { whatever.... } );
Data will be passed back in JSON format. IN your case, you can access data[0] which is "my";