SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

I've spend over 6 hours to find an exception or a special character to find in my code but I couldn't. I checked every similar messages in here.

I'm sending the form with magnific popup. First I'm using inline popup to open my form than I'm sending all inputs to main.js to validate.

So, I just need a third-eye.

I've got: index.html, register.php, main.js

> Here's the code

FORM

JS/AJAX

PHP-register.php

> Here goes the error messages

JSON Output

Chrome Console:

Firefox console :

---

What am i missing?

For the benefit of searchers looking to solve a similar problem, you can get a similar error if your input is an empty string.

e.g.

var d = "";
var json = JSON.parse(d);

or if you are using AngularJS

var d = "";
var json = angular.fromJson(d);

In chrome it resulted in 'Uncaught SyntaxError: Unexpected end of input', but Firebug showed it as 'JSON.parse: unexpected end of data at line 1 column 1 of the JSON data'.

Sure most people won't be caught out by this, but I hadn't protected the method and it resulted in this error.

The fact the character is a < make me think you have a PHP error, have you tried echoing all errors.

Since I don't have your database, I'm going through your code trying to find errors, so far, I've updated your JS file

$("#register-form").submit(function (event) {
 
    var entrance = $(this).find('input[name="IsValid"]').val();
    var password = $(this).find('input[name="objPassword"]').val();
    var namesurname = $(this).find('input[name="objNameSurname"]').val();
    var email = $(this).find('input[name="objEmail"]').val();
    var gsm = $(this).find('input[name="objGsm"]').val();
    var adres = $(this).find('input[name="objAddress"]').val();
    var termsOk = $(this).find('input[name="objAcceptTerms"]').val();
 
    var formURL = $(this).attr("action");
 
 
    if (request) {
        request.abort(); // cancel if any process on pending
    }
 
    var postData = {
        "objAskGrant": entrance,
        "objPass": password,
        "objNameSurname": namesurname,
        "objEmail": email,
        "objGsm": parseInt(gsm),
        "objAdres": adres,
        "objTerms": termsOk
    };
	
	$.post(formURL,postData,function(data,status){
		console.log("Data: " + data + "\nStatus: " + status);
	});
 
	event.preventDefault();
});

PHP Edit:

 if (isset($_POST)) {
 
    $fValid = clear($_POST['objAskGrant']);
    $fTerms = clear($_POST['objTerms']);
 
    if ($fValid) {
        $fPass = clear($_POST['objPass']);
        $fNameSurname = clear($_POST['objNameSurname']);
        $fMail = clear($_POST['objEmail']);
        $fGsm = clear(int($_POST['objGsm']));
        $fAddress = clear($_POST['objAdres']);
        $UserIpAddress = "hidden";
        $UserCityLocation = "hidden";
        $UserCountry = "hidden";
 
        $DateTime = new DateTime();
        $result = $date->format('d-m-Y-H:i:s');
        $krr = explode('-', $result);
        $resultDateTime = implode("", $krr);
 
        $data = array('error' => 'Yükleme Sırasında Hata Oluştu');

        $kayit = "INSERT INTO tbl_Records(UserNameSurname, UserMail, UserGsm, UserAddress, DateAdded, UserIp, UserCityLocation, UserCountry, IsChecked, GivenPasscode) VALUES ('$fNameSurname', '$fMail', '$fGsm', '$fAddress', '$resultDateTime', '$UserIpAddress', '$UserCityLocation', '$UserCountry', '$fTerms', '$fPass')";
        $retval = mysql_query( $kayit, $conn ); // Update with you connection details
            if ($retval) {
                $data = array('success' => 'Register Completed', 'postData' => $_POST);
            }
   
        } // valid ends
    }echo json_encode($data);

Remove

 dataType: 'json'

replacing it with

 dataType: 'text'

I have the exact same issue and I've found something. I've commented the line :

dataType : 'json',

after that it was successful but... when I did console.log(data) it returned the main index.html.

That's why you have "Unexpected token <" error and it cannot parse.

Changing the data type to text helped dataType: 'text'

I have check with JSONlint and my json format was proper. Still it was throwing error when I set dataType: 'json'

JSON Data: {"eventinvite":1,"groupcount":8,"totalMessagesUnread":0,"unreadmessages":{"378":0,"379":0,"380":0,"385":0,"390":0,"393":0,"413":0,"418":0}} 

Are you sure you are not using a wrong path in the url field? - I was facing the same error, and the problem was solved after I checked the path, found it wrong and replaced it with the right one.

Make sure that the URL you are specifying is correct for the AJAX request and that the file exists.

Sending JSON data with NodeJS on AJAX call :

$.ajax({
	url: '/listClientsNames',
	type: 'POST',
	dataType: 'json',
	data: JSON.stringify({foo:'bar'})
}).done(function(response){
	console.log("response :: "+response[0].nom);
});

Be aware of removing white spaces.

app.post("/listClientsNames", function(req,res){
		
		var querySQL = "SELECT id, nom FROM clients";	
		var data = new Array();
		
		var execQuery = connection.query(querySQL, function(err, rows, fields){
			
			if(!err){
				for(var i=0; i<25; i++){
					data.push({"nom":rows[i].nom});			
				}
				res.contentType('application/json');
				res.json(data);	
			}else{	
				console.log("[SQL005] - Une erreur est survenue");
			}

		});
			
});

I have got same Error while fetch data from json filesee attached link

"SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data"

So, i check the path of the json file which isn't correct,

const search = document.getElementById("search");
const matchList = document.getElementById("match-list");

//search json data and filter
const searchStates = async searchText => {
    const res = await fetch('../state.json');
    const states = await res.json();
    console.log(states);
}

search.addEventListener('input', () => searchStates(search.value));

so that i changed the path of the file

const res = await fetch('./state.json');

& it gives me array back as a result. so, check your path & try changed it. It will work in my case. I hope that's works..

JSON.parse() doesn't recognize That data as string. For example {objAskGrant:"Yes",objPass:"asdfasdf",objNameSurname:"asdfasdf adfasdf",objEmail:"[email protected]",objGsm:3241234123,objAdres:"asdfasdf",objTerms:"CheckIsValid"}

Which is like this: JSON.parse({objAskGrant:"Yes",objPass:"asdfasdf",objNameSurname:"asdfasdf adfasdf",objEmail:"[email protected]",objGsm:3241234123,objAdres:"asdfasdf",objTerms:"CheckIsValid"}); That will output SyntaxError: missing " ' " instead of "{" on line...

So correctly wrap all data like this: '{"objAskGrant":"Yes","objPass":"asdfasdf","objNameSurname":"asdfasdf adfasdf","objEmail":"[email protected]","objGsm":3241234123,"objAdres":"asdfasdf","objTerms":"CheckIsValid"}' Which works perfectly well for me.

And not like this: "{"objAskGrant":"Yes","objPass":"asdfasdf","objNameSurname":"asdfasdf adfasdf","objEmail":"[email protected]","objGsm":3241234123,"objAdres":"asdfasdf","objTerms":"CheckIsValid"}" Which give the present error you are experiencing.

Even if your JSON is ok it could be DB charset (UTF8) problem. If your DB's charset/collation are UTF8 but PDO isn't set up properly (charset/workaround missing) some à / è / ò / ì / etc. in your DB could break your JSON encoding (still encoded but causing parsing issues). Check your connection string, it should be similar to one of these:

$pdo = new PDO('mysql:host=hostname;dbname=DBname;**charset=utf8**','username','password'); // PHP >= 5.3.6

$pdo = new PDO('mysql:host=hostname;dbname=DBname','username','password',**array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8")**); // older versions

P.S. Outdated but still could be helpful for people who're stuck with "unexpected character".

May be its irrelevant answer but its working in my case...don't know what was wrong on my server...I just enable error log on Ubuntu 16.04 server.

//For PHP
error_reporting(E_ALL);
ini_set('display_errors', 1);

When the result is success but you get the "<" character, it means that some PHP error is returned.

If you want to see all message, you could get the result as a success response getting by the following:

success: function(response){
     var out = "";
     for(var i = 0; i < response.length; i++) {
        out += response[i];
     }
     alert(out) ;
},

In some cases data was not encoded into JSON format, so you need to encode it first e.g

 json_encode($data);

Later you will use json Parse in your JS, like

JSON.parse(data);

Try using MYSQLI_ASSOC instead MYSQL_ASSOC... usually the problem is solved changing that

Good luck!

I had the same error in an AJAX call in an app with pagination and or in any case with a query string in the URL

since AJAX was posting to something like

var url = window.location.href + 'search.php';
...
...
fetch(url, {
        method: 'POST', 
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({search: text}),
      })

as soon in the browser URL was added some query string, the error "JSON.parse: unexpected character at line 1 column 1" was popping

the solution has been to simply clean the URL from any query string with

var url = window.location.href.split('?')[0] + 'search.php';

and issue got fixed

So, the error was not the formatting of the Json, instead it was a wrong URL for the POST

@Prahlad is on to something here. I've been seeing this thing for years and it just became background noise to me.

Recently I was doing some brand new stuff and I realized I was seeing that in my console (FF 98.0 (64-bit)) on Mac (12.2.1 (21D62)) where the html is being served by a local NGNIX install (nginx/1.21.6)

Here is the html being served, in it's entirety:

<!doctype html>
<html lang="en">
<head>
</head>
<body>
   Some text
</body>
</html>

Now... I don't have a clue why it is happening, but I'm pretty sure it's not the code :-)