how to get the correct value from json (php)? - php

Question

update_modal(bootstrap)
<div class="modal fade" id="updateModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">Edit：</h5>
<button class="close" type="button" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body" id="body">
<input type="text" class="form-control" placeholder="product_title" id="title">
</div>
<div class="modal-footer">
<button class="btn btn-secondary" type="button" data-dismiss="modal">Cancel</button>
<a class="btn btn-primary" href="login.php">Update</a>
</div>
</div>
</div>
</div>
trigger the update_modal(bootstrap)
<td>
<a data-toggle='modal' data-target='#updateModal'>
<button class='btn btn-success' id='edit' data-id='$product_no'>Edit</button>
</a>
</td>
js
<script>
$(document).ready(function() {
$(document).on('click','#edit',function () {
let id=$(this).attr('data-id');
// console.log(id);
$.ajax({
url:'get_record.php',
method:'post',
data:{
p_no:id
},
dataType:'JSON',
success:function (data) {
// $('#body').html(data);
console.log(data[0]);
console.log(data[1]);
console.log(data[2]);
}
});
});
})
</script>
get_record.php
<?php
include ("db.php");
global $conn;
if (isset($_POST['p_no'])){
$p_no=$_POST['p_no'];
$query="select * from products where p_no='$p_no'";
$result=mysqli_query($conn,$query);
while($row=mysqli_fetch_array($result)){
$user_data=' ';
$user_data [0]=$row['product_title'];
$user_data [1]=$row['date'];
$user_data [2]=$row['product_price'];
// echo $pro_title;
}
echo json_encode($user_data);
}
My problem is when I click the edit button, the update_modal displays successfully, but it doesn't get correct values from my database. I click F12 on my chrome and it tested like this photo

Answer 1

You are initializing $user_data in get_record.php as a string: $user_data = ' ';
Try initializing that variable as an array instead: $user_data = [];
Because you initialize $user_data as a string, setting $user_data[0] only sets the first character of the string to the first character of the value $row['product_title'].
EDIT: As noted in the comments, you are also opening yourself up to SQL injection attacks by inserting posted data directly into your SQL here:
$p_no=$_POST['p_no'];
$query="select * from products where p_no='$p_no'"
You should escape all user inputs before using them in a query. One way to do that for MySQL in PHP:
$p_no=mysqli_real_escape_string($_POST['p_no']);
$query="select * from products where p_no='$p_no'"
Using prepared statements would be ideal.