Question

I am trying to create a weekly calendar that allows the user to advance or go back a week. So far I have this…

<?
if(isset($_POST['add_week'])){
     $last_week_ts = strtotime($_POST['last_week']);
     $display_week_ts = $last_week_ts + (3600 * 24 * 7);
} else if (isset($_POST['back_week'])) {
     $last_week_ts = strtotime($_POST['last_week']);
     $display_week_ts = $last_week_ts - (3600 * 24 * 7);
} else {
    $display_week_ts = floor(time() / (3600 * 24)) * 3600 * 24;
}

    $week_start = date('d-m-Y', $display_week_ts);
    $week_number = date("W", strtotime( $display_week_ts));
    $year = date("Y", strtotime( $display_week_ts));

echo $week_start.' '.$week_number.' '.$year;
?>

<table name="week">
    <tr>
<?
for($day=1; $day<=7; $day++)
{
    echo '<td>';
    echo date('d-m-Y', strtotime($year."W".$week_number.$day))." | \n";
    echo '</td>';
}
?>
</tr>
<tr>
<form name="move_weeks" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<input type="hidden" name="last_week" value="<? echo $week_start; ?>" />
<td colspan="7"><input type="submit" name="back_week" value="back_week" /><input type="submit" name="add_week" value="add_week" />
</td>
</form>
</tr>
</table>

The the back and forward buttons work just fine and the $week_start variable which represents the first date of the week advances and goes back as it should but regardless of the date shown the $week_number and $year show as 01 and 1970 or 36 and 1600.

I know it must be something to do with the way I have tried to extract them from $display_week_ts but I don’t know what

Answer 1

The following looks out of place:

$week_start = date('d-m-Y', $display_week_ts);
$week_number = date("W", strtotime( $display_week_ts));
$year = date("Y", strtotime( $display_week_ts));

See how you’re using $display_week_ts in the first statement, but for the other (and similar) statements, you wrap that timestamp inside a call tostrtotime() which returns false.

It’s best to just drop the strtotime() and use the variable as is:

$week_number = date("W", $display_week_ts);
$year = date("Y", $display_week_ts);