How to calculate the time comparison and difference between PHP

<?php   2. $zero 1=date ("y-m-d h:i:s");   3. $zero 2 = "2010-11-29 21:07:00′;   4. Echo "Zero1 time:". $zero 1. " <br> ";   5. Echo "Zero2 time:". $zero 2. " <br> ";   6. if (Strtotime ($zero 1) <strtotime ($zero 2)) {   7.  echo "Zero1 earlier than zero2′;   8.}else{   9.  echo "Zero2 earlier than zero1′;   Ten.}   ?>

Above is the size of the comparison two absolute time

<?php   $zero 1=strtotime (Date ("y-m-d h:i:s"));//Current Time  , note H is 24 h is 12 hours $zero 2=strtotime ("2014-1-21 00:00:00 ");  Chinese New Year, can not write 2014-1-21 24:00:00  so not $guonian =ceil (($zero 2-$zero 1)/86400);//60s*60min*24h   echo "< from New Year's Day strong> $guonian </strong> Days! ";   ? >  

Above is the Countdown applet instance code

<?php//php calculates the method of two time difference $startdate = "2010-12-11 11:40:00"; $enddate = " 2012-12-12 11:45:09 "; $date =floor ((Strtotime ($enddate)-strtotime ($startdate))/86400); $hour =floor ((Strtotime ($ EndDate)-strtotime ($startdate))%86400/3600), $minute =floor ((Strtotime ($enddate)-strtotime ($startdate))%86400/60 ); $second =floor ((Strtotime ($enddate)-strtotime ($startdate))%86400%60); Echo $date. " Day <br> "Echo $hour." H <br> "; Echo $minute." Minutes <br> "Echo $second." SEC <br> ";? 

<?php/** * Time Difference calculation * * @param Timestamp $time * @return String time Elapsed * @author Shelley Shyan * @copyright http://p   hparch.cn (Professional PHP Architecture) */function time2units ($time) {$year = floor ($time/60/60/24/365);   $time-= $year * 60 * 60 * 24 * 365;   $month = Floor ($time/60/60/24/30);   $time-= $month * 60 * 60 * 24 * 30;   $week = Floor ($time/60/60/24/7);   $time-= $week * 60 * 60 * 24 * 7;   $day = Floor ($time/60/60/24);   $time-= $day * 60 * 60 * 24;   $hour = Floor ($time/60/60);   $time-= $hour * 60 * 60;   $minute = Floor ($time/60);   $time-= $minute * 60;   $second = $time;   $elapse = "; $UNITARR = Array (' Year ' = ' + ' Years ', ' month ' = ' ' month ', ' Week ' = ' ' Week ', ' Day ' = ' ~ ', ' hour ' = ' hour ', '   Minutes ' = ' minute ', ' sec ' = ' second ');           foreach ($unitArr as $CN = + $u) {if ($ $u > 0) {$elapse = $ $u. $CN;       Break   }   }return $elapse;} $past = 2052345678;     Some timestamp in the Past$now = Time (); Current Timestamp$diff = $now-$past; Echo ' Posted in '. Time2units ($diff). ' former ';? >

　　

How to calculate the time comparison and difference between PHP