How to calculate the time comparison and difference between PHP

1.<?PHP 2.$zero 1 =Date ("Y-m-d h:i:S "); 3.$zero 2 = "2010-11-29 21:07:00; 4. echo "Zero1 time is:".  $zero 1. " <br>"; 5. echo "Zero2 time is:".  $zero 2. " <br>"; 6. if (strtotime ($zero 1) <strtotime ($zero 2)) {7. echo "Zero1 earlier than zero2′; 8.}Else{9. echo "Zero2 earlier than zero1′; Ten. } 11. ?>                   

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 hours h is 12 hours  $zero 2=strtotime ("2014-1-21 00:00:00"); // New Year time, cannot write 2014-1-21 24:00:00 this does not  $guonian =ceil ( $zero 2- $zero 1)/86400); //60s*60min*24h echo " <strong> $guonian </strong>               

Above is the Countdown applet instance code

<?php//PHP calculates two time-difference methods$startdate = "2010-12-11 11:40:00";$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. " Hours <br> "; echo  $minute. " Minutes <br> "; echo  $second. " Seconds <br> "

 

<?php
/**
* Time Difference calculation
*
* @param Timestamp $time
* @return String Time Elapsed
* @author Shelley Shyan
* @copyright http://phparch.cn (Professional PHP Architecture)
*/
functionTime2units($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 (Years=' Year ',' A month '=' Month ',Week=' Week ',Days=' Day ',
Hours=' Hour ',Minutes=' Minute ',Seconds=' Second '
);

foreach ($unitArrAs$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