how to use JSON.stringify and json_decode() properly

Question

When you save some data using JSON.stringify() and then need to read that in php. The following code worked for me.

json_decode( html_entity_decode( stripslashes ($jsonString ) ) );

Thanks to @Thisguyhastwothumbs

When you use JSON stringify then use html_entity_decode first before json_decode.

$tempData = html_entity_decode($tempData);
$cleanData = json_decode($tempData);

You'll need to check the contents of $_POST["JSONfullInfoArray"]. If something doesn't parse json_decode will just return null. This isn't very helpful so when null is returned you should check json_last_error() to get more info on what went wrong.

None of the other answers worked in my case, most likely because the JSON array contained special characters. What fixed it for me:

Javascript (added encodeURIComponent)

var JSONstr = encodeURIComponent(JSON.stringify(fullInfoArray));
document.getElementById('JSONfullInfoArray').value = JSONstr;

PHP (unchanged from the question)

$data = json_decode($_POST["JSONfullInfoArray"]);
var_dump($data);

echo($_POST["JSONfullInfoArray"]);

Both echo and var_dump have been verified to work fine on a sample of more than 2000 user-entered datasets that included a URL field and a long text field, and that were returning NULL on var_dump for a subset that included URLs with the characters ?&#.

stripslashes(htmlspecialchars(JSON_DATA))

jsonText = $_REQUEST['myJSON'];

$decodedText = html_entity_decode($jsonText);

$myArray = json_decode($decodedText, true);`