Select Dropdown for Hours in the day. Value is ready for string to time conversion.

hours_dropdown.php

<select>
    <?php $first = false;
    for($t = 12; $t<=23; $t++): ?>
        <?php for($m = 0; $m<=45; $m+=15): ?>
            <?php $m = $m == 0 ? sprintf("%02s", $m): $m; ?>
            <option value="<?php echo ($t == 12 && !$first ? '00' : ($t < 10 ? '0'.$t : $t)).':'.$m.':00'; ?>">
                <?php echo $t > 12 ? ($t-12 == 0 ? 12 : $t-12).':'.($m).' PM' : $t.':'.$m.' AM'; ?>
            </option>
        <?php endfor; ?>
        <?php if($t == 12 && !$first){
            $first = true;
            $t = 0;
        }
        endfor;?>
</select>