Decoding json object retrieved from PHP in Javascript

Question

I am having trouble using the json object echoed from php to javascript. In the php file I define

$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
echo($json);

and then in javascript file I want to access this object.

$("#test_btn").click(function() {
                $.get("serverside.php", function(data, status) { 
                   console.log("data " , data["a"]); //undefined
                   console.log(JSON.parse(data)); // error
                });
            });

I get undefined for data["a"] and an error for JSON.parse. How should I use the returend data?

Use an associative array and echo it with json_encode. Don't create your own JSON, it's prone to errors. — elclanrs
– elclanrs, Commented May 15, 2014 at 22:16
Try just console.log(data) and see what it outputs. You're probably not getting valid JSON — itsananderson
– itsananderson, Commented May 15, 2014 at 22:20
Which error are you getting? The error message usually helps. — Felix Kling
– Felix Kling, Commented May 15, 2014 at 22:23
I think I realized the problem, yet I don't know how to solve it! in the php file, I am reading the content of several json files, so I loop through all the files and echo in the loop. I thought the content of each file comes separately but accually what I get is a "{"a":1,"b":2,"c":3,"d":4,"e":5}{"a":1,"b":2,"c":3,"d":4,"e":5}{"a":1,"b":2,"c":3,"d":4,"e":5}..." which is not valid json — hAlE
– hAlE, Commented May 15, 2014 at 22:26
Read the contents of all your json files and put them in a PHP array with json_decode function. Once they're in a format you're happy with export them with json_encode. — user115014
– user115014, Commented May 15, 2014 at 22:56

jeroen · Accepted Answer · 2014-05-15 22:29:19Z

3

Based on your comment (echoing several json strings), you should do the following:

Initialize an empty results array;
Read your file and put it in an array or object using json_decode();
Add this array / object to your results array;
At the end, use json_encode() to encode and echo out your results array.

answered May 15, 2014 at 22:29

jeroen

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Comments

Sergio Flores · Accepted Answer · 2014-05-15 22:24:23Z

1

You must make a JSON.parse(data) before attempting to access to data['a'], and send a header from PHP that implicitly say the browser that the data output is going to be a JSON.

header ('Content-Type: application/json');

answered May 15, 2014 at 22:24

Sergio Flores

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2 Comments

jeroen Over a year ago

jQuery will make an intelligent guess and if it recognizes the json, it will be parsed already by the time you get it.

Rahil Wazir Over a year ago

It doesn't matter to the order of JSON.parse(data) on success callback, as it actually trigger an error which indicates it just parsed invalid json.

user115014 · Accepted Answer · 2014-05-15 22:39:12Z

0

The problem might be that PHP is returning a string that looks like JSON.

In JS it might help to JSON.parse(data) to convert from string to JSON object, then you can access it.

$("#test_btn").click(function() {
  $.get("serverside.php", function(data, status) {
    $json = JSON.parse(data);
    console.log("data " , $json["a"]); // should now return 1
  });
});

answered May 15, 2014 at 22:39

user115014

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Comments

Frenetika · Accepted Answer · 2014-05-15 22:41:09Z

0

you need to put json_encode or parse it in javascript

answered May 15, 2014 at 22:41

Frenetika

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