0825-02-for-color-picker.php

<!doctype html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        td {
            width: 30px;
            height: 30px;
        }
    </style>
</head>

<body>
    <table>
        <?php for ($i = 0; $i <= 255; $i += 17) : ?>
            <tr>
                <?php for ($k = 0; $k <= 255; $k += 17) : ?>
                    <td style="background-color: #<?= sprintf("%'.06X", $i * 256 + $k) ?>"></td>
                <?php endfor ?>
            </tr>
        <?php endfor ?>
    </table>
    <script>
        const table = document.querySelector('table');
        table.addEventListener('click', function(event) {
            const t = event.target;
            console.log(t.style.backgroundColor);
        });
    </script>
</body>

</html>