search.php

<?php
$con = mysqli_connect('localhost', 'root', '', 'payment');
$out = '';
$sql = "SELECT * FROM student WHERE username LIKE '%" . $_POST['search'] . "%'";
$run_sql = mysqli_query($con, $sql);

if (mysqli_num_rows($run_sql) > 0) {
?>
<ul>
    <img src="./images/loading.gif" alt="loading animation" align='center'
        style='width: 20px;height: 20px;margin: 0 auto'>
    <?php
        while ($row = mysqli_fetch_array($run_sql)) {
            $id = $row['id_student'];
            $user_name = $row['username'];
        ?>
    <li class="" id="element">
        <a href="py.php?student=<?php print $id; ?>">
            <?php print $user_name; ?>
        </a>
    </li>
    <?php
        }
        ?>
</ul>
<?php
} else {
    echo "<p class='alert alert-success red m-3'><b>" . $_POST['search'] . "</b> element is not recognized into our system </p>";
}