PHP日期递增错误

Question

I am trying to create a calendar where the date increments and each date is clickable, which links to a search. The strange part is that the date stops at 25th October, and stops incrementing. i.e 24th, 25th, 25th, 25th...

Its doesn't matter which day the calendar started with (been staring at it for a few days), but at 25th it stops incrementing.

Grateful for any advice.(The 2nd part after the gap is probably irrelevant, but including it in case there could be any link)

for ($i = 1; $i <= 30; $i++){ 
    $date = date("d-m-Y", strtotime($date) + 86400);
    array_push($array_date, $date);
    $separatedate = explode('-', $date);   
    $getday = date("l", strtotime($date));
    print "<button class='submitsearch btn' value=$array_date[$i]>" . ltrim($separatedate[0], '0') . "<br>" . $getday . "<br></button>";

    if (!checkdate($separatedate[1] , $separatedate[0]+1 , $separatedate[2])) {
        $nextmonth = date("F", strtotime($date) + 86400);
       print "<strong>". $nextmonth . "</strong><hr/>";
    }
}

Answer 1

This is the problem:

$date = date("d-m-Y", strtotime($date) + 86400);

You appear to be relying on that to increment the date. Usually, that will be fine... but it isn't when we have a 25 hour day, due to daylight saving time changes.

I suggest you use date/time arithmetic functions (e.g. date_add) designed to add a day, rather than adding 24 hours. Or make sure all arithmetic is done in UTC, which won't have any time zone changes. In general, I would try to avoid performing any more string conversions than you really need to: keep a variable representing the date/time in an idiomatic way, and perform arithmetic on that - then just format that variable when you need to. I don't see any need to call strtotime anywhere, if you do this right.