PHP and javascript Array Literals

I need help, sending data from the server.

$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$sql = "SELECT id, voltage/*, current_out, power ,temperature,  reading_time*/ FROM SensorData GROUP BY id;";



$result = mysqli_query($conn,$sql);
$data1= array();

    
foreach ($result as $row) {
    $data1[] = $row;
}

    $result->close();

shaped

[{"id":"36","voltage":"16"},{"id":"37","voltage":"18"},{"id":"38","voltage":"20"},{"id":"39","voltage":"22"},{"id":"40","voltage":"26"},{"id":"41","voltage":"30"},{"id":"42","voltage":"32"},{"id":"43","voltage":"34"},{"id":"44","voltage":"36"},{"id":"45","voltage":"36"}] 

and I process but I don’t know exactly how to approach individual parameters. you don’t know where the problem is.

<script >
 
     $(document).ready(function(){
  $.ajax({
    url: "http://192.168.1.16/webput_to_mysql.php",
    method: "GET",
    success: function(data1) {
       console.log(data1);
         var voltage1 = [];
         var id1 = [];
        voltage1.push(data1[1].voltage);
      document.getElementById("demo").innerHTML = voltage1;
    }
  });
});

</script>

enter image description here

Answer

The problem is that the data is coming back as a string, and you’re trying to read it as JSON. You can just add the dataType option to ajax, to tell jQuery how to handle things.

$.ajax({
    url: "http://192.168.1.16/webput_to_mysql.php",
    method: "GET",
    dataType: "json",
    ...
});

See the docs for more info.

Another option is to send the json header in PHP (before your echo json_encode...), which should help jQuery detect the type automatically:

header('Content-Type: application/json');