Question

I am preparing and sending a JSON string from my PHP file to my Javascript function like this:

$json = array();
$json['slice'] = false;
$json['G500'] = false;
$json['KG1'] = false;   

$encoded = json_encode($json);
die($encoded);

However, in my JS function, if I do this, it is unable to decode the JSON object:

var d = req.responseText;                                           
var jsonObject = eval(d);

The only way, I can get it to eval the JSON object is by adding parentheses manually

jsonObject = eval("(" + d + ")");

I have the same problem going in reverse as well. Sending a JSON object to PHP and trying to decode it there fails. I believe I would need to remove the parentheses in my PHP script before attempting to decode.

Why is this happening? Is there something I can do to work around this incompatibility?

EDIT:

PHP to JS is now working if I use JSON.parse. I’m still having trouble the other way around.

This is how I’m sending the data to the PHP:

var JSONstring = 
{
    "Product": document.getElementById('item').value, 
    "Size": document.getElementById('size').value,
    "Quantity": document.getElementById('quantity').value                                                   
};

url = "maintainOrder.php?json=" + JSON.stringify(JSONstring);

req.open("GET", url, true);

However, the PHP script is unable to decode it.

$newItem = json_decode($_GET['json']);

array_push($_SESSION['order'],$newItem);

Answer 1

For the php to javascript issue refer to the Tomalak Geret’kal answer.

For the javascript to php maybe I have the solution:

If you want an associative array in php then you have to pass assoc parameter as true into json_decode (default to false)

Example:

$array = json_decode($jsonString, true);

I was bitten a couple of times by this: by default json_decode try to create an object if it receive a javascript object (it make perfect sense if you think of) and you have to force it to render an associative array if you need this behaviour