checkbox checked after reloading pages and backing to previous page

I need only which I checked! not all.

<?php if (isset($_SESSION["design"])) { ?>
<input type="checkbox" onkeypress="isInputNumber(event)" name="design" value="<?php echo $design_id; ?>" checked>
<?php } else {?>
<input type="checkbox" onkeypress="isInputNumber(event)" name="design" value="<?php echo $design_id; ?>">
<?php } ?>