JSON vs. Arrays

What is JSON

• JSON = JavaScript Object Notation
• Object that contains Data
• Better than XML for use with Javascript (cause it is not a markup language and it is lightweight)
• Easier and quicker to setup than XML on the server-side

JSON vs. Arrays

• JSON wins
• Not a good comparison since JSON can have arrays inside of it
• JSON can store nested objects and arrays, it is much more powerful than an array

What does JSON look like?

Declaring an empty JSON object in Javascript:

var data = {};

A basic JSON object:

var data = {kind: "Human", water: "Clear Blue", help: false};

A complex JSON object:

var bar = {prop: [{key: "Value", x: "yes"},{alien: false, skin: "Green Tone"}], sand:true};

var data = {kind: "Human", water: "Clear Blue", help: false, extra: bar};

How do I set it up a JSON in PHP?

A simple example that outputs a static JSON object:

<?

header("Content-type: application/json");

echo '{"items: [ key: "value", another_key: { k: "val", x: "yes" } ]}';

?>

Convert PHP arrays into JSON:

<?

header("Content-type: application/json");

$my_object = '{"items: [ key: "value", another_key: { k: "val", x: "yes" } ]}';

$count = 2;

echo json_encode(array("items" => $my_object, "count" => $count));

?>

Get data from a database and turn it into JSON with PHP:

<?

$input = $_GET["q"];

$data = array();

// query your DataBase here looking for a match to $input

$query = mysql_query("SELECT * FROM my_table WHERE my_field LIKE '%$input%'");

while ($row = mysql_fetch_assoc($query)) {

$json = array();

$json['value'] = $row['id'];

$json['name'] = $row['username'];

$json['image'] = $row['user_photo'];

$data[] = $json;

}

header("Content-type: application/json");

echo json_encode($data);

?>

Using JSON with jQuery

Query the server and alert some JSON data:

$.getJSON("http://mysite.com/path/to/script", function(data){

var items = data.items[0];

alert(items.key);

});