Why doesn't my ajax work with prepared mysqli statement - php

Question

I have a small problem, which is that when I add my prepared statement into the PHP file, the Ajax stops working and gives me a 500- error, but when I remove the statement, it works like a charm.
This is my PHP file:
<?php
include ('db_connect.php');
include ('functions.php');
$datad = $_POST['superstr'];
$id = 1;
$stmt = $mysqli->prepare("UPDATE `song` SET `lyrtext`=? WHERE `id`=?");
$stmt->bind_param("si", $datad, $id);
$status = $stmt->execute();
echo $datad;
?>
and my Ajax looks like this:
$.ajax({
url: 'includes/sendlyrics.php',
type: 'POST',
data: {superstr: 'pelle'},
success: function(data) {
//called when successful
var hello = data;
//prompt(data);
console.log("The data is:");
console.log(data);
console.log("The variable which should keep the data has this content:");
console.log(hello);
},
error: function(e) {
//called when there is an error
console.log(e.message);
prompt(e.message);
//alert(e.message);
}
});
What's the problem?

Answer 1

$stmt = $mysqli->prepare("UPDATE `song` SET `lyrtext`=? WHERE `id`=?");
$stmt->bind_param("si", $datad, $id);
$status = $stmt->execute();
Is wrong. Amend this to:
$stmt = $mysqli->prepare("UPDATE `song` SET `lyrtext`=? WHERE `id`=?");
$stmt->bind_param("si", $datad, $id);
$stmt->execute();
If you are looking for confirmation of the query executing successfully you can test this by:
if($stmt->execute()){
//returned true - statement executed successfully
} else{
//returned false
}
Also you should modify your Ajax call to something similar to:
$.ajax({
url : "your/url/here.php"
type : "POST",
data : {superstr: 'pelle'},
dataType : "json",
success : function(data){
//do something with the response
},
error : function(jqXHR, textStatus, errorThrown){
//handle the error
}
});
By adding a dataType of json, you should then ammend the echo statement of your .php file to read:
$response = Array();
array_push($response, $datad);
echo json_encode($response);
I'm sure you've read the documentation online already, but Ajax can be found here, and prepared statements here.
This is all written with the caveat that your DB connection is valid...which it would appear to be given the wording of your question, and your previous attempts at solving the issue.