Access array in Javascript

Question

I cannot seem to understand why I cannot access an array I get send back by PHP.

I send this back when AJAX makes a call: $response['success'] = true;

I do this by echo json_encode($response); in my PHP file.

Now I want to access it in Javascript, but response.success doesnt work, it logs 'undefined' in the console. Now I check the response, and that is this: {"success":false}

But if I check for if(response.success) it always sends back false, because response.success is undefined. Does anyone know what I mean and what is causing this issue?

This is my AJAX call:

$$.ajax({
    type: 'POST',
    url: url + "applogin.php",
    crossDomain: true,
    data: {
        username: e,
        password: p
    },
    //dataType: 'json', 
    success: function(response) {
        console.log(response);

        if (response["success"]) {

            window.localStorage["username"] = e;
            window.localStorage["password"] = md5(p);

            mainView.router.loadPage('beurslist.html');
        } else {

            console.log("Your login failed");
        }
    },
    error: function(jqXHR, textStatus, errorThrown) {
        console.log("Error- Status: " + textStatus + " jqXHR Status: " + jqXHR.status + " jqXHR Response Text:" + jqXHR.responseText)
    },

});

response.success should be the way. Are your sure you are returning the correct JSON? What does console.log(response) output? — linkyndy
– linkyndy, Commented May 17, 2015 at 17:28
You have to set dataType option to json. Otherwise the response will be treated as html (by default) — hindmost
– hindmost, Commented May 17, 2015 at 17:34
@hindmost - From the docs: dataType (default: Intelligent Guess (xml, json, script, or html)) — Jared Farrish
– Jared Farrish, Commented May 17, 2015 at 18:06

avnr · Accepted Answer · 2015-05-17 19:42:17Z

2

The answer by @SZenC is fine, there's a point though about best practices:

The reason jQuery didn't recognize the response as JSON is because the server probably didn't send a Content-type header, so just add to your server-side code a call to -

header('Content-type: text/json');

You won't need the explicit call to JSON.parse in each API call, you'll get better integration with test tools, and your app will be better self-documented for other folks who use/will-use this code (including yourself should your code need some future maintenance).

In any case it is advised also to document the expected input on the client side by either explicitly specifying dataType as json or by making the API call using a shortcut method such as $.getJSON().

answered May 17, 2015 at 19:42

avnr

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CerebralFart · Accepted Answer · 2015-05-17 18:05:11Z

1

Your ajax-call will return a string, you need to decode it with JSON.parse. You'd get something like this then.

$$.ajax({
  type: 'POST',
  url: url + "applogin.php",
  crossDomain: true,
  data: {
    username: e,
    password: p
  },
  //dataType: 'json', 
  success: function(r) {
    var response=JSON.parse(r)
    console.log(response);
    if (response["success"]) {
      window.localStorage["username"] = e;
      window.localStorage["password"] = md5(p);
      mainView.router.loadPage('beurslist.html');
    } else {
      console.log("Your login failed");
    }
  },
  error: function(jqXHR, textStatus, errorThrown) {
    console.log("Error- Status: " + textStatus + " jqXHR Status: " + jqXHR.status + " jqXHR Response Text:" + jqXHR.responseText)
  }
});

answered May 17, 2015 at 18:05

CerebralFart

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2 Comments

Kuubs Over a year ago

Thank you! This is indeed the way, i feel stupid for overseeing such a simple mistake.

CerebralFart Over a year ago

@HuubS, it happens to the best of us

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