Ajax: I can't get data from PHP by using json_encode - php

Question

I am having issues retrieving data from PHP by using Ajax. I am stuck and have been spending lots of time trying to find out where the problem is.
Here is my php code:
<?php //ajax/default_chart_numbers.php
require_once '../core/db_connection.php';
$lotto = new Lotto();
$ultimo_concurso=$lotto->ultimo_concurso('foo');
$ultimos_numeros_m=$lotto->ultimos_numeros('bar');
$R1m=$ultimos_numeros_m[1];
$R2m=$ultimos_numeros_m[2];
$R3m=$ultimos_numeros_m[3];
$R4m=$ultimos_numeros_m[4];
$R5m=$ultimos_numeros_m[5];
$R6m=$ultimos_numeros_m[6];
$R7m=$ultimos_numeros_m[7];
//preparing json
$json=array('y'=>$ultimo_concurso,'n1'=>$R1m,'n2'=>$R2m,'n3'=>$R3m,'n4'=>$R4m,'n5'=>$R5m,'n6'=>$R6m);
print json_encode($json,true);
?>
The output of the PHP file is:
{"y":"2745","n1":"1","n2":"13","n3":"19","n4":"29","n5":"41","n6":"46"}
And here is the jQuery code:
<script>
$(document).ready(function(){
/*Retriving data from PHP file*/
$.ajax({
url: "ajax/default_chart_numbers.php",
cache: false,
dataType: "json",
timeout:3000,
success : function (response, textS, xhr) {
alert("everything ok :)");
},
error : function (xmlHttpRequest, textStatus, errorThrown) {
alert("Error " + errorThrown);
if(textStatus==='timeout')
alert("request timed out");
},
complete: function(data){
y=data.y;
alert('The id number is '+ y);
}
});
});
</script>
When executing, the value is undefined. I mean, the alert i get is The id number is undefined.
What am i missing?

Answer 1

There's no true in json_encode, there is in json_decode to get an array, but now you're creating a string
change
print json_encode($json,true);
to
echo json_encode($json);
and the complete handler doesn't get the data, it has two arguments, the XHR object and the statuscode, the success handler gets the data
$.ajax({
url: "ajax/default_chart_numbers.php",
cache: false,
dataType: "json",
timeout:3000,
success : function (data) {
y=data.y;
alert('The id number is '+ y);
},
error : function (xmlHttpRequest, textStatus, errorThrown) {
alert("Error " + errorThrown);
if(textStatus==='timeout')
alert("request timed out");
}
});

Answer 2

On PHP side, send the JSON with:
header('Content-Type: application/json');
echo json_encode($json);
Maybe log the incoming data to the console:
inside success: add an console.log(response)
inside complete: add an console.log(data.y)

Answer 3

This is missing:
https://api.jquery.com/jQuery.parseJSON/
try using:
result = $.parseJSON (data);
result.y has your value