jquery ajax请求中的未定义索引错误

Question

Please check my code in the following:

PHP & HTML Code(file1.php):

<?php
$conn = //connected to db successfully.
$sql = "SELECT t1.column1 AS Column_1 FROM table1 t1";
$rs = mysqli_query($conn,$sql);
$rows= mysqli_fetch_assoc($rs);
do{
?>
<button data-id="<?php echo $rows['Column_1']; ?>" type="button" onclick="handle_item('id')">Click Me</button> <br>
<?php }while($rows = mysqli_fetch_assoc($rs)); ?>

jQuery AJAX code(file1.php):

<script type="text/javascript">
    var item_id;
    function handle_item(item_id) {
        var c = $(this).data(item_id);
        $.ajax({
            url: 'handle_input.php',
            type: 'POST',
            data: {
                'button_id': c
            },
            success: function (data) {
                alert(data);
            }
        });
    }
</script>

PHP Code(handle_input.php):

<?php
echo "Button with id ".$_POST['item_id]." clicked!";
?>

Now the problems is (as you might expect) the infamous error in this case, "undefined index: button_id" error. I receive it as an alert error when I click on one of the buttons. I've already read the duplicate questions on SO but unfortunately none of those I read could resolve my problem. I appreciate your guiding me with this.

Besides, as you see from my codes, I'm fetching several button from database and while displaying, I assign each one a data-id and use that data-id in ajax to use in 'handle_input.php' and I want to receive each button id which I've clicked on. Thanks in advance.

UPDATE:

It's been a while since I've asked this question but I've been curios about something in my question: Why doesn't the array mode(data: {"button_id":c}) work for me in the $.ajax function(which leads to undefined index error for the $_POST variable) whereas the string mode(data: "usg_id="+c) does?

Answer 1

You're sending:

button_id:..

but you're using, also with a missing '

$_POST['item_id]

change to:

$_POST["button_id"]

UPDATE

Add this as first parameter:

onclick="handle_item(this, 'id')"

Then, changehandle_item function as this:

function handle_item(obj,item_id) {
    var c = $(obj).data(item_id);