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Request issue: Uncaught SyntaxError: Unexpected token /

I am developing i small app that displays some JSON data
inside of a listview. To receive the data I am using a simple request.
And I am getting always the same issue:
Uncaught SyntaxError: Unexpected token :
my code:
$.ajax({
url: 'http://localhost/documents.json',
data: {
format: 'json'
},
error: function() {
$('#info').html('<p>An error has occurred</p>');
},
dataType: 'jsonp',
success: function(data) {
// do something with the data
},
type: 'GET'
});
});
My JSON file is valid. I checked it with a JSON validator.

Invalid JSON (no matter how mangled) cannot generate a JavaScript syntax error if you parse it with JSON.parse() or any decent dedicated parser (and that's what jQuery does). The same happens with all other standard data types (XML, HTML, plain text...). All symptoms suggest you're expecting JSONP but getting some other data type. The builtin browser network pane should reveal what you're getting exactly.
Whatever, if you only want JSON and nothing but JSON you should simplify your code as follows:
Omit protocol and host:
url: 'http://localhost/documents.json',
should be:
url: '/documents.json',
(Probably not required, but will help to void errors.)
Ask for the correct data type:
dataType: 'jsonp',
should be:
dataType: 'json',
Do not parse again what jQuery already parsed for you:
var json = $.parseJSON(data);
should be:
var json = data; // Yeah, nothing :)
This should be enough for local AJAX. If you really need a cross-site request (I asked twice and never got an answer) you have to tweak your server to either return the appropriate CORS headers or implement JSONP data type and change your client-side code accordingly because you'll no longer have JSON—because JSONP is not JSON!

Check if your json is valid by using jsonlint.com or you can use jsonmate.com. These are very helpful to me when I'm debugging json.
Also - it would help to have a link to the full code. Use jsfiddle.net to put your code into - then link it to this post. This will help the community debug your code.

Javascript json parsing of php response

I'm working on a project and use ajax to update some informations in forms.
Here is my ajax function :
function update_ad() {
var project_name = document.getElementById("mol_project").value;
if (project_name !== '') {
$.ajax({
type: 'POST',
url: "controllers/get_project.php",
data: {project_name: project_name},
dataType: 'text',
success: function (data) {
var result = JSON.parse(data);
}
});
}
}
On my development environement everything works fine. The function get the json text from php server and parse it so I can use data after that.
But on my production environement, I receive a parsing error :
SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data
Here is the received Json :
{"project_name":"Jaguar","project_ORB_code":null,"project_manager":null,"project_abbr":"JR","project_mol_index":"2","project_comment":null}
Jquery, apache and php version are the same on both environements. I guess it's a server configuration issue but I can't figure out where it is.

replace dataType: 'text' to dataType: json,
Look at the spec for JSON (easily understood version here: http://json.org/). There is nowhere that says that parenthesis are valid. ({"foo": true}), for example will never parse. It may be evaled as it is valid javascript, but javascript is not JSON.

Okay, in your JSON, there's a UTF-8 BOM in the front. Can you find the difference between:
{"project_name":"Jaguar","project_ORB_code":null,"project_manager":null,"project_abbr":"JR","project_mol_index":"2","project_comment":null}
And:
{"project_name":"Jaguar","project_ORB_code":null,"project_manager":null,"project_abbr":"JR","project_mol_index":"2","project_comment":null}
Where the latter is a valid JSON. Check it out with JSONLint. You need to make sure that the output you are receiving is free of UTF-8 BOM.
When I tried using the encodeURI() function on the JSON, it gave me this output:
encodeURI(' {"pr'); // "%20%EF%BB%BF%7B%22pr" - Wrong one!
encodeURI(' {"pr'); // "%20%7B%22pr" - Correct one!
We can make use of encodeURI to detect the anamolies and fix it in the client side. I am working on a solution.
The unicode signature, if you see, is EF BB BF, which is explained in this article. We can make use of this signature and try to correct it.
If you have the access to the PHP source, try setting the right headers:
header("Content-type: application/json; charset=utf-8");

executing ajax success function- jQUERY

I've searched around for this error and none of the solutions appear to help me with what I am getting. I am doing an ajax request, and I am trying to retrieve the json output released by the server. I can print out the json that i am trying to capture (via console.log()) not process it in the jQuery.parsejson(). I keep getting a "Uncaught SyntaxError: Unexpected token o" error. Please can someone advise?
my code:
// Make ajax request
$.ajax({
url: 'http://localhost/multipleFileUpload_adam/webservice/delete_pdf.php',
data: {delete_array: jsonString},
dataType: 'json',
type: 'POST',
success: function(data){
console.log(data);
var x = jQuery.parseJSON(data);
},
console.log(data) gives the following ( am trying to retrieve the 'success_deleted' array:
Object {success_delete: Array[2], unsuccess_delete: Array[0], input array: Object}
if I remove the line of code :
var x = jQuery.parseJSON(data);
Then I am able to get the console.log(data) to work. if i add it i get the error mentioned above.

This line:
dataType: 'json',
tells jQuery to ignore the content-type returned by the server and always parse the response as if it was JSON.
Then:
success: function(data){
The JavaScript value (which is an object) that you get from parsing the JSON is passed into data.
This line:
jQuery.parseJSON(data);
Takes the value of data (an object)
Converts it into a string (which will be "[object Object]")
Tries to parse that string as JSON (which it isn't).
Then I am able to get the console.log(data) to work. if i add it i get the error mentioned above.
Yes. That is the expected behaviour. Don't do that. Just work with the already parsed data in data.

there is a parse error because data is already an object so it is expecting json and getting Object. 'O' is the unexpected character. Try without the parseJSON function.

Uncaught SyntaxError: Unexpected token : - data still coming through

I'm very new to JSON and JSONP.
I've read through each of the posts that are recommend by the SO search for this error, but I can't seem to get a handle on it.
I have the following code to grab data from an EXTERNAL website:
$.ajax({
url: "https://url.com/authenticate?login=test&apiKey=test",
dataType: 'jsonp',
success:function(json){
console.log("login successful");
}
});
When I load the page, I get:
Uncaught SyntaxError: Unexpected token :
and when I click on the error in Chrome, I see
{"Status":{"Code":"2","Message":"Authentication Succeeded","Success":"true"}}
with a little red x after "true"})
From this, it seems as though I have succeeded in logging in, but I'm doing something else wrong because my console.log("login successful"); never fires. What am I doing wrong?
P.S.
I've tried dataType: 'json' but I get the No 'Access-Control-Allow-Origin' header is present as I'm on a different server, so I went back to jsonP as this is cross-domain.
I've also tried the above url as url: "https://url.com/authenticate?login=test&apiKey=test&callback=?", as I've read I need a callback, but I don't really understand what the functionality of callback is and either way, the error that gets returned (whether &callback=? is in there or not) is:
authenticateUser?login=test&apiKey=test&callback=jQuery111107732549801003188_1423867185396…:1 Uncaught SyntaxError: Unexpected token :
so it's adding the callback in either way....
Also, from the API I'm trying to access:
"this uses the REST protocol, and provides data structured as XML or JSON"
This is not a duplicate of the linked post as the information in the linked post does a great job of explaining what JSONP is, but doesn't answer my specific question regarding why I get data back (so my call is successful,) but why I still get an error and cause my script to stop.

The API you're sending the AJAX request doesn't implement JSONP. It ignores the callback= parameter, and just returns ordinary JSON. But when the browser tries to process this as JSONP, it gets a syntax error because it's not properly formatted. JSONP is a JSON object wrapped in a call to the specified callback function, e.g. it should be sending back:
jQuery111107732549801003188_1423867185396({...});
where {...} is the JSON object you're trying to retrieve. But it's just returning {...}.
You should implement this using a PHP script on your own server. It can be as simple as this:
<?php
$username = urlencode($_POST['user']);
readfile("https://url.com/authenticate?login=$username&apiKey=test");
Then your AJAX call would be:
$.ajax({
url: "yourscript.php",
type: "post",
dataType: "json",
data: { user: "test" },
success: function(json) {
console.log("login successful");
}
});

Why do I get Uncaught SyntaxError: Unexpected token ILLEGAL

I want to use AJAX and the SoundCloud API to get the tracks of a user.
jQuery.ajax({
url: 'http://api.soundcloud.com/resolve?url=http://soundcloud.com/[SOME USER]/tracks/&format=json&consumer_key=[MY KEY]&callback=?'
, dataType: 'jsonp'
, success: function( data ) {
console.log( data );
}
});
I can see that chrome gets the json data but I get the error
Uncaught SyntaxError: Unexpected token ILLEGAL
in the console.
The issue is probably that the json file is an json array. Could that be the error?
And if yes, how can I convert the array into single objects?

The problem is that the description field in track id #159500192 ('Summer Chords Pt. 2' (Electro House Mix)) has invisible characters that are not legal inside of JavaScript strings, so the JavaScript parser chokes when trying to the run the JSONP response as a script. SoundCloud should encode these values when serving content via JSONP.
Because SoundCloud supports CORS, you don't need to use JSONP at all. You can simply request the file directly, by removing the callback=? parameter and using dataType: json (not jsonp):
jQuery.ajax({ url: "https://api.soundcloud.com/resolve?url=http://soundcloud.com/[USER]/tracks/&format=json&consumer_key=[KEY]",
dataType: 'json',
success: function(d) { console.log(d); }
});