Pass Javascript variable in PHP query – Mysql

From what I can tell by looking at the structure of your modal, you seem to be using Bootstrap, though I am unclear on the version. If it’s Bootstrap 5, read on. If not, please add that information to your question, and let me know.

Here’s how you can do it all in one call.

First, change the page from which you are opening the modal, so that the modal isn’t a part of it. You need to make a separate file to hold the modal contents. Let’s call that file remote-file.php. This would be inside that file.

<?php
    // your PHP logic goes here - parse the received $_POST parameters, prepare your query - if needed, query your database
    // retrieve the data, and place it in variables for later display

    require 'conn.php';
    $jvid = isset($_POST['jvid'] ? (int)$_POST['jvid'] : 0;

    $result = $conn->prepare("SELECT job_desc FROM jobspervisit WHERE jvid = ? AND job_desc='Fumes'");
    $result->bind_param("i",$jvid);
    $result->execute();

    if($result && $result->num_rows == 1) {
        // row found, do stuff
        $output = '<a href="print/print_fumes_card.php" target="_blank" class="btn btn-success pull-left"><span class="glyphicon glyphicon-print"></span>print button</a>';
    } else {
        $output = "Nothing found";
    }
?>
<div class="modal-dialog">
    <form method="post" id="job_form" enctype="multipart/form-data">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal">&times;</button>
                <h4 class="modal-title">Jobs</h4>
            </div>
            <div class="modal-body">
                <div id="show_inseredjobs"></div>
                <br/>
                <select name="job_desc" class="form-control action" id="job_desc" data-live-search="true"  title="Select Job"></select>
            </div>
            <div class="modal-footer">
            <input type="hidden" name="vis_id" id="vis_id" value="<?=$jvid?>">
        <?php
            echo $output;
        ?>
                <input type="submit" name="action" id="action" form="job_form" class="btn btn-success" value="Προσθήκη" />
                <button type="button" class="btn btn-default" data-dismiss="modal">Άκυρο</button>
            </div>
        </div>
    </form>
</div>

Some notes about previous code:

• it is assumed that jvid in your database is an INT type colum. Because of that, we could do (int)$_POST['jvid']
• if jvid is not an INT but another type of column, we wouldn’t do the (int)$_POST['jvid'] bit, and our binding would be slightly different

    // prepare the query
    $jvid = $_POST["jvid"];
    $results = $conn->prepare("SELECT job_desc FROM jobspervisit WHERE jvid = ? AND job_desc='Fumes'");
    $results = $conn->bind_param("s",$jvid);
    $result->execute();

Next, in the original page, where your buttons are (and where your modal’s HTML was), you would need this line of code for the modal.

<div class="modal fade" id="jobModal"></div>

This is going to be a wrapper for your modal content. All the rest will be going inside the remote-file.php. Also, your button element, the one that’s opening the modal on click? That button doesn’t need to have a data-bs-target attribute, because the following code will work (since you’re using jQuery and all).

<button class="btn btn-lg btn-success add-task" id="btn" data-id="1234">Open modal</button>

<div class="modal fade" id="jobModal"></div>

<script>
    $(document).ready(function() {
        $(document).on('click', '.add_task', function(){
            var user_id = $(this).attr("id");

            $('#jobModal').load('remote-file.php',{'jvid':user_id },function(){
                var jobModal = new bootstrap.Modal($('#jobModal')[0], {
                    backdrop:"static",
                    show:true
                });

                jobModal.show();
            });
        });
    });
</script>

Final notes:

• jQuery version: 3.6.3
• Bootstrap version: 5.3.0