PHP: How do I can decode a json back into array form in Javascript?

Question

I've an array in my php called as $tempoHeader, for example:

Example Array $tempoHeader

-------
Array
(
   [0] => red
   [1] => green
   [2] => yellow
   [3] => blue
)

I want to send it into my external javascript, so I do this one in my php code:

My PHP: header.php

$tempoHeader = array_diff_assoc($modelData, $data);
<script type="text/javascript">var header = <?php echo json_encode($tempoHeader); ?>;</script>
<script type="text/javascript" src="upload_header.js"></script>

In my javascript, I've try to console.log(header); and I got this in my console

Array [ "red", "green", "yellow", "blue" ]

My JS: upload_header.js

$(window).load(function() {
console.log(header);                    //this work and print out the header json
   var myObject = JSON.parse(header);
   var myArray = jQuery.parseJSON(header);
   console.log(myArray);                   //didn't print out anything
   console.log(myObject);                  //didn't print out anything
});

How do I can decode this json back as $tempoHeader array form?

Note: I've read this issue jQuery JSON Decode ( PHP to Javascript), and I've try the suggestion such as jQuery.parseJSON(header);, JSON.parse(header); but I got nothing

score 1 · Answer 1 · edited Jan 27 '17 at 08:33

1

$res = json_decode( $tempoHeader, true );
echo $res->array_name[index];

I hope this help

edited Jan 27 '17 at 08:33

Naga

2,190
3
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answered Jan 27 '17 at 08:26

Divyam Solanki

461
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That returns stdClass/object. Pass true as second argument – Adam Azad Jan 27 '17 at 08:27

jeroen · Answer 2 · 2017-01-27T08:37:12.653

header already is an array, it is not json / a string and you do not need to parse it.

You send this to javascript:

var header = <?php echo json_encode($tempoHeader); ?>;

So you already have an array in javascript as you have noticed:

Array [ "red", "green", "yellow", "blue" ]

And then you try to parse that as json:

var myObject = JSON.parse(header);

That is not possible nor is it necessary: json is a string and JSON.parse() expects a string as its parameter. You cannot use it on an array.

To use your variable, you can simply use header[0] (red), etc. or loop over it like you do with any other javascript array.

Yah, you're right. My var `header` is already as an array :) thanks a lot :) — Blackjack, Jan 27 '17 at 14:09

score 0 · Answer 3 · answered Jan 27 '17 at 08:34

The Problem here is that when you executes your JavaScript, your PHP Script was already executed, to "send a variable back to php" you have to create a new Request.

Mostly it is done via Ajax OR you can add your Array in a hidden input field and "send" it with a form.

So you upload_header.js would look like

   $(function () {

        $.ajax('update_header.php', {
            method: 'POST',
            data: {
                'header': JSON.stringify(header)
            }
        })
    });

and in your "update_header.php" you would recieve the new header with

$newHeader = json_decode($_POST['header'],true);

hope this helps;)

PHP: How do I can decode a json back into array form in Javascript?

Example Array $tempoHeader

My PHP: header.php

My JS: upload_header.js

How do I can decode this json back as $tempoHeader array form?

3 Answers3