Php alt-checkbox demo snippet

alt-checkbox-demo.php

<?php if (isset($_POST['checkbox1'])) : ?>
    <p style="color: #ffa500">Checked!</p>
<?php endif; ?>

<form action="demo.php" method="post">
    <input type="checkbox" id="checkbox1" name="checkbox1" <?php if (isset($_POST['checkbox1'])) : ?> checked<?php endif; ?>>
    <label for="checkbox1" >Check Me! I'm medium.</label>
    <br><br>
    <input type="submit">
</form>

<script>
    jQuery("#checkbox1").altCheckbox();
</script>