برای محاسبه چندروز قبل و بعد فقط کافیه مقدار عدد 3 را افزایش یا با تغییر علامت + به - روز قبل رو محاسبه کنیم

 

 

include ('jdf.php');
$timezone = 0;
$now = date("Y-m-d", time()+$timezone);
$time = date("H:i:s", time()+$timezone);
$threeDaysAgo = time() + (3 * 24 * 60 * 60);
list($year, $month, $day) = explode("-" , date("Y-m-d", $threeDaysAgo));
list($hour, $minute, $second) = explode(':', $time);
$timestamp = mktime($hour, $minute, $second, $month, $day, $year);
$cy = $jalali_date = jdate("Y m d",$timestamp);
echo $cy;