Can't post JSON variable with AJAX to PHP - php

Question

In the first document I added a JSON string filled with numbers to localstorage like this:
$.ajax({
url: "oyvind_liste.php",
data: {aktuelle_verdier: aktuelle_verdier},
dataType: "json",
success: function(result){
var dataToStore = JSON.stringify(result);
localStorage.setItem('key', dataToStore);
}});
Then in another document I am trying to post the JSON string retrieved from local storage like this:
<script>
var data = JSON.parse(localStorage.getItem('key'));
var localData = data.join(", ");
$.ajax({
type: 'post',
data: {localData: localData},
url: '',
dataType: "json",
success: function(result){
console.log(result)
}});
</script>
The PHP on the same page as the post tries to fetch the data like this:
<?php
$user_id = isset($_POST['localData'])?$_POST['localData']:"";
$values = json_decode($user_id);
var_dump($values);
?>
When I run var_dump I get Array(), so in essence it doesn't post anything. Anyone know whats going wrong?

Answer 1

You don't need to use JSON when sending an array in an object argument to $.ajax. Just put the array there, and jQuery will URL-encode it.
var data = JSON.parse(localStorage.getItem('key'));
$.ajax({
type: "post",
data: { localData: data },
...
});
Then in PHP you can do:
$values = isset($_POST['localData']) ? $_POST['localData'] : array();
var_dump($values);
You can also send JSON this way:
var json_string = localStorage.getItem('key');
$.ajax({
type: "post",
data: { localData: json_string},
...
});
then in PHP do:
$values = json_decode(isset($_POST['localData']) ? $_POST['localData'] : '[]');
var_dump($values);