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The JSON example page
The JSON PHP page
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Quercus has built-in JSON support and JSON functionality is enabled the moment Quercus is started: no additional downloads are required. Quercus sports two PHP functions for working with JSON: json_encode and json_decode.

<example> json_encode(mixed php_object) encodes any PHP array or object into JSON. json_decode(string json_string [, bool is_assoc]) decodes JSON into a PHP array or object. </example>

json_decode may return either a PHP array or object depending on the circumstances:

- If the text is that of a JSON array, decoding returns a non-associative PHP array.
- If the text is that of a JSON object and the second argument to json_decode is not specified or is false, decoding returns a standard PHP object.
- If the text is that of a JSON object and the second argument to json_decode is true, then decoding returns an associative PHP array.

To encode an array into JSON:

<example> <?php $array = array("a"=>"Caucho", "b"=>"Resin", "c"=>"Quercus"); $json = json_encode($array); ?> </example>

The value of $json would be: '{"a":"Caucho", "b":"Resin", "c":"Quercus"}'. The JSON text may then be sent and used on the user's browser or to any client that can decode JSON.

To decode JSON data into a standard PHP object in Quercus (using the above JSON text $json as an example):

<example> <?php $object = json_decode($json); ?> </example>

$object would be a standard PHP object with three fields "a", "b", and "c" with values "Caucho", "Resin", and "Quercus" respectively.

Below is a simple example using JSON on the web.

<example> <script type="text/javascript"> <?php $array = array("a"=>"Caucho", "b"=>"Resin", "c"=>"Quercus"); $json = json_encode($array); echo "var data = $json;"; ?> var decoded = eval("(" + data + ")"); //Should output: "Quercus at work." document.write(decoded.c + " at work."); </script> </example>

JSON data is more commonly sent to the browser via AJAX requests. Suppose there are two files defined below. The PHP script in json.php encodes an array into JSON. When the user's browser is directed to json.html, an AJAX request receives JSON data from json.php. Then the browser calls `eval()` on the JSON data to recover a JavaScript object.

<example> <?php $array = array("a"=>"Caucho", "b"=>"Resin", "c"=>"Quercus"); $json = json_encode($array); echo $json; ?> </example> <example> <html> <head> <script type="text/javascript"> var url = "data.php"; function request() { if (window.XMLHttpRequest) http_request = new XMLHttpRequest(); else http_request = new ActiveXObject("Microsoft.XMLHTTP"); http_request.onreadystatechange = function() { handle_json(http_request) }; http_request.open("GET", url, true); http_request.send(null); } function handle_json(http_request) { if (http_request.readyState == 4) { document.firstForm.json.value = http_request.responseText; var decoded = eval("(" + http_request.responseText + ")"); document.firstForm.decoded.value = decoded.a + "'s " + decoded.b + " with " + decoded.c + " at work."; } } function clearForm() { document.firstForm.json.value = ""; document.firstForm.decoded.value = ""; } </script> </head> <body> <form name="firstForm"> <p>JSON:<br><textarea name="json" cols="50"></textarea></p> <p>Decoded:<br><textarea name="decoded" cols="50"></textarea></p> <input type="button" onclick="request()" value="AJAX Request"> <input type="button" onclick="clearForm()" value="Clear"> </form> </body> </html> </example>

- Official JSON Homepage
- JSON Wikipedia entry
- Caucho's JSON Wiki entry
- C Implementation from which Quercus' JSON syntax is based off of

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