Develop Reference

Why am i getting undefined while trying to access the value in json data returned via ajax

data[0] correctly returns the 0th line of the json data but trying to access the key like service and online returns undefined.
<script>
$.ajax({
url:"count.php",
dataType:'json',
success: function(data, status){
console.log(data[0].online);
}
});
</script>
count.php
<?php
$data = array();
$data[] = file_get_contents('https://xxxxxik.php?%20metod=get_count_new%20&service=pro1&apikey=sdss');
$data[] = file_get_contents('https://xxxxxik.com/priemnik.php?%20metod=get_count_new%20&service=pro2&apikey=sdds');
echo json_encode($data);
?>
console.log(data) prints the below json
[
"{\"service\":\"pro1\",\"online\":91}",
"{\"service\":\"pro2\",\"online\":0}"
]

The array data contains strings. You can use Array​.prototype​.map()and JSON.parse() to convert it to array of objects.
$.ajax({
url:"count.php",
dataType:'json',
success: function(data, status){
data = data.map(x => JSON.parse(x))
console.log(data[0].online)
}
});

You need to parse the data first:
<script>
$.ajax({
url:"count.php",
dataType:'json',
success: function(data, status){
data = JSON.parse(data);
console.log(data[0].online);
}
});
</script>

Unexpected token in JSON at positon 0

I always get Unexpected token in JSON at positon 0 in my code
the echo json will be
["pen","pencil","apple","cat","dog"]
and the console will get Uncaught SyntaxError: Unexpected token p in JSON at position 0
php code :
<?php
include 'Connect_2.php';
header('Content-Type: application/json;charset=utf-8');
$Store_int =$_GET['num'];
#execute sql function and return result
$sql = "SELECT * FROM `store` WHERE `Place_int` = ".$Store_int;
mysqli_select_db($link,"web");
$link -> set_charset("utf8");
$result = mysqli_query($link,$sql);
$arr = array();
while ($row = mysqli_fetch_object($result)){
$p =(string) $row -> Name;
$arr[]=$p;
}
//print_r($arr);
$jsonArr = json_encode($arr,JSON_UNESCAPED_UNICODE);
echo ($jsonArr);
mysqli_free_result($result);
mysqli_close($link);
?>
.js code
function getArr(store_int){
var jsArray = new Array();
$.ajax({
url: "fromSQL_store.php",
data: {
num: store_int
},
type: "GET",
dataType: "json",
success: function(data) {
jsArray = JSON.parse(data);
//jsArray = data;
},error: function(data,XMLHttpRequest, textStatus, errorThrown){
console.log(textStatus);
console.log(errorThrown);
}
});
//alert(jsArray.length);
console.log(jsArray[0]);
return jsArray;
}
if I use jsArray = data ;the console(jsArray[0]) will show undefined.

It's already JSON. Don't call jsArray = JSON.parse(data); Instead, just treat data like a JSON object.
Instead of console(jsArray[0]) call console(jsArray) The data object doesn't seem to be an array.
Also, it looks like you're console.log is being called right after you send the ajax request, which isn't giving you any time to receive the response to populate the object, so it's going to be empty. Put the console.log in the success callback of the ajax request.
JSON.parse() throws this error when it's parsing something that's already JSON which is really annoying since it sure would be nice if it instead just returned the original JSON back to you or at least threw a more precise error like "Error: This is already JSON."

May be your response header Content-Type is text/html instead of application/json.
Hence, If the response header is text/html you need to parse the text into JSON Object but if the response header is application/json then it is already parsed into JSON Object.
The solution is to set correct Content-Type header.
If response header (Content-Type) is text/html :
var jsonObj = JSON.parse(responseData);
If response header (Content-Type) is application/json :
var jsonObj = responseData;

pass php array to javascript using ajax

I try to get array from sql server using php , and parsing these array to javascript using ajax.
However , I have tried many solution by google , I can't get the array.
This is my php code:
<?php
include 'Connect.php';
$Store_int = $_GET['num'];
$sql = "SELECT * FROM `store` WHERE `Place_int` = " . $Store_int;
mysqli_select_db($link, "web");
$link->set_charset("utf8");
$result = mysqli_query($link, $sql);
$arr = array();
while ($row = mysqli_fetch_object($result)) {
$p = (string)$row->Name;
$arr[] = $p;
}
//print_r($arr);
$jsonArr = json_encode($arr, JSON_UNESCAPED_UNICODE);
echo $jsonArr;
mysqli_free_result($result);
mysqli_close($link);
?>
Array in php will encode and display:
["pen","pencil","apple","cat","dog"]
and the .js file
function getArr(store_int) {
var jsArray = new Array();
$.ajax({
url: "fromSQL_store.php",
data: {
num: $("#store_int").val()
},
type: "GET",
dataType: "json",
success: function (data) {
alert(num);
jsArray = JSON.parse(data.jsonArr);
}, error: function (data) {
alert("123");
}
});
//alert(jsArray.length);
return jsArray;
}
In .js , I will always get empty response(undefined) from php.
Because the ajax will answer "error" function..., and the error status is 200.

Your array will always return undfined as the AJAX call is async, your function returns jsArray before it is set. and You don't need JSON.parse() as you have defined dataType as json in your ajax call. Pass a function to your getArr() function and use your data in that function.
function getArr(store_int, outputFn){ // what do you use store_int for?
$.ajax({
url: "fromSQL_store.php",
data: {
num: $("#store_int").val()
},
type: "GET",
dataType: "json",
success: function(data) {
outputFn(data)
},error: function(data){
alert("123");
}
});
}
Then use it like
getArr('5', function (data) {
console.log(data)
})
Console output

Your problem lies here. You are attempting to access data.jsonArr which is always undefined. The JSON data sent is actually embodied by data variable.
success: function(data) {
alert(num);
jsArray = JSON.parse(data.jsonArr); // Replace by jsArray = data;
}
NOTE, You might also need to specify that the MIME media type that is being outputted is JSON. Putting this at the top of your PHP script should solve your problem.
<?php
header('Content-Type: application/json');

How to access the data in the object returned by an ajax call [duplicate]

This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 8 years ago.
I make an AJAX request:
function getdbsite(wantedid) {
alert(wantedid);
$.ajax({
url: 'public/xml/xml_getdbsite.php',
dataType: 'text',
data: {"wantedid": wantedid},
type: 'POST',
success: function (data) {
resultObj = eval(data);
site=resultObj[0];
// alert(site->language); }These cause errors
// alert(site->name); }
reply=resultObj[1];
}
});
}
The server side PHP:
<?php
error_reporting(E_ALL);
ini_set('display_errors', '1');
require_once '../../includes/initialize.php';
header("Content-Type: application/json");
$id=$_POST['wantedid'];
$site = Website::find_by_id($id);
if($site){
$arr[0] = $site;
$arr[1] = "OK";
}else {
$arr[0] = "$id";
$arr[1] = "Failed";
}
$arr = json_encode($arr);
echo("$arr");
AJAX responce: [{"id":"19","idlanguage":"1","name":"QI"},"OK"]
But I am unable to access the db row.
I have searched and found:
Parse PHP array of objects with jQuery Ajax
but do not understand the answers, their examples only have 1 field. Please help.

I strongly suggest don't use eval() function for this.
Instead, explicitly set that you are going to receive JSON from the server:
dataType: 'JSON',
Example:
PHP:
if($site){
$arr['data'] = $site;
$arr['message'] = "OK";
}else {
$arr['data'] = $id;
$arr['message'] = "Failed";
}
echo json_encode($arr);
exit;
JS:
$.ajax({
url: 'public/xml/xml_getdbsite.php',
dataType: 'JSON',
data: {"wantedid": wantedid},
type: 'POST',
success: function(response) {
// use dot notation not -> arrow notation
var data = response.data;
var message = response.message;
alert(message);
alert(data.id);
alert(data.idlanguage);
}
});

Loop Through json_encoded PHP Array in JavaScript

I am having an issue with looping through an array that was passed from PHP through an Ajax request.
For some reason my javascript thinks that either every character is a part of the array or my response variable is just being passed as a string.
Here is my javascript:
<script>
$(function() {
$.ajax({
url: "/dev/editButton/get_names.php",
success: function(response) {
console.log(response);
}
});
});
</script>
And here is my PHP:
<?php
include '../portfolio/libraries/settings.php';
$connect = mysqli_connect($HOST, $DB_USER, $DB_PASS, $DATABASE);
$query = "SELECT * FROM AUTH_User";
$result = mysqli_query($connect, $query);
$names = array();
while ($row = mysqli_fetch_array($result)) {
array_push($names, $row['FirstName']." ".$row['LastName']);
}
echo json_encode($names);
?>
The response that I get looks like this:
["Test Person","Test2 Person"]
However, if I loop through this using javascript or just print out response[0] I get each character as part of the array. The first element would be [, next would be ", etc.
I would like Test Person to be one element and Test2 Person to be another.
Does anybody know what I am doing wrong? Thanks!

You need to use JSON.parse on the response. Wihtout calling that function you are just getting the index of characters in the JavaScript string.
var resultArray = JSON.parse(response);
resultArray[0]; //Should Be "test Person"

The result of the .ajax method is interpreted according to the Content-Type header of the response. If it is incorrect or not specified, the response variable will contain the raw json code as a string.
So one solution is change the PHP code by adding this line:
header("Content-Type: text/json");
Docs:
The type of pre-processing depends by default upon the Content-Type of
the response, but can be set explicitly using the dataType option. If
the dataType option is provided, the Content-Type header of the
response will be disregarded.
You can parse that text to an object, or you can let JQuery do that for you by specifying a datatype in the call. The response parameter will then hold the object instead of the raw json string.
Docs:
If json is specified, the response is parsed using jQuery.parseJSON
before being passed, as an object, to the success handler. The parsed
JSON object is made available through the responseJSON property of the
jqXHR object.
$(function() {
$.ajax({
url: "/dev/editButton/get_names.php",
datatype: "json",
success: function(response) {
console.log(response);
}
});
});

In this particular situation, you can use
success: function(response) {
response = eval(response);
console.log(response);
}
But this is bad practice.
Really the best solution here is to modify your ajax call as follow:
$(function() {
$.ajax({
url: "/dev/editButton/get_names.php",
datatype: 'json',
success: function(response) {
console.log(response);
}
});
});
The specified datatype, will request the returned data to be json, and the jquery will automatically parse it to a javascript object.

You must parse JSON to array. You can do this using the following code:
var arr = $.parseJSON(response);
Now arr[0] should be "Test Person".

You can do it the hard way, or this way:
First, you need to specify the return type for AJAX.
$(function() {
$.ajax({
url: "/dev/editButton/get_names.php",
dataType: "json",
success: function(response) {
console.log(response);
}
});
});
Alternatively, you could do it this way:
$(function() {
$.getJSON("/dev/editButton/get_names.php", function(response) {
console.log(response);
});
});
For this to work, you will need to specify the HTML headers accordingly in PHP:
<?php
include '../portfolio/libraries/settings.php';
$connect = mysqli_connect($HOST, $DB_USER, $DB_PASS, $DATABASE);
$query = "SELECT * FROM AUTH_User";
$result = mysqli_query($connect, $query);
$names = array();
while ($row = mysqli_fetch_array($result)) {
array_push($names, $row['FirstName']." ".$row['LastName']);
}
header("Content-Type: application/json");
echo json_encode($names);
exit();
?>
The exit(); is just for safety so you wouldn't ruin the valid JSON format.
JSON stands for JavaScript Object Notation, so you should not have to do anything complicated there. Here is a simple loop you could use for example:
for(var i in response) {
console.log(response[i]);
}
Alternatively, if the response is not an array but an object with properties, you could loop through the object properties by getting the right keys first:
var objKeys = Object.keys(response);
for(var i in objKeys) {
var key = objKeys[i];
console.log(response[key]);
}
I hope this helps!