Summary of commonly used PHP date functions

Summary of commonly used date functions in PHP: including checking whether the date format is legal, checking whether the time is legal, time comparison functions, and returning seconds, minutes, hours or days between two dates.

function check_date($date) { //Check whether the date is a legal date
 $dateArr = explode("-", $date);
 if (is_numeric($dateArr[0]) && is_numeric ($dateArr[1]) && is_numeric($dateArr[2])) {
 return checkdate($dateArr[1],$dateArr[2],$dateArr[0]);
 }
 return false;
}
 function check_time($time) { //Check whether the time is legal time
 $timeArr = explode(":", $time);
 if (is_numeric($timeArr[0]) && is_numeric($timeArr[1]) && is_numeric ($timeArr[2])) {
 if (($timeArr[0] >= 0 && $timeArr[0] <= 23) && ($timeArr[1] >= 0 && $timeArr[1] <= 59) && ($timeArr[2] >= 0 && $timeArr[2] <= 59))
 return true;
 else
 return false;
 }
 return false;
}

function DateDiff ($date1, $date2, $unit = "") { //Time comparison function, returns the seconds, minutes, hours or days between two dates
 switch ($unit) {
 case 's':
 $dividend = 1;
 break;
 case 'i':
 $dividend = 60;
 break;
 case 'h':
 $dividend = 3600;
 break;
 case 'd':
 $dividend = 86400;
 break;
 default:
 $dividend = 86400;
 }
 $time1 = strtotime($date1);
 $time2 = strtotime($date2);
 if ($time1 && $time2) //OSPHP.COM.Cn Open source
 return (float)($time1 - $time2) / $dividend;
 return false;
}

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