PHP 日期加减的类，很不错

　　$temptime = time();

　　echo strftime ( "%Hh%M %A %d %b" , $temptime );

　　$date = new DateAccount();

　　$temptime = $date ->DateAdd( "n" ,50, $temptime );

　　echo "<p>" ;

　　echo strftime ( "%Hh%M %A %d %b" , $temptime );

　　$temptime = time();

　　echo strftime( "%Hh%M %A %d %b",$temptime);

　　$date = new DateAccount();

　　$temptime = $date->DateAdd("n" ,50,$temptime);

　　echo "<p>";

　　echo strftime( "%Hh%M %A %d %b",$temptime);

　　$currenttime = time();

　　echo "Current time: " . strftime ( "%Hh%M %A %d %b" , $currenttime ). "<br>" ;

　　$date = new DateAccount();

　　$newtime = $date ->DateAdd ( "n" ,50 , $currenttime );

　　echo "Time plus 50 minutes: " . strftime ( "%Hh%M %A %d %b" , $newtime ). "<br>" ;

　　$temptime = $date ->DateDiff ( "n" , $currenttime , $newtime );

　　echo "Interval between two times: " . $temptime ;

　　$currenttime = time();

　　echo "Current time: ". strftime("%Hh%M %A %d %b" ,$currenttime)."<br>";

　　$date = new DateAccount();

　　$newtime = $date->DateAdd ("n",50 ,$currenttime);

　　echo "Time plus 50 minutes: ". strftime("%Hh%M %A %d %b" ,$newtime)."<br>";

　　$temptime = $date->DateDiff ("n",$currenttime ,$newtime);

　　echo "Interval between two times: ".$temptime;

　　<?php

　　class DateAccount{

　　function __construct(){

　　}

　　function DateAdd ( $interval , $number , $date ) {

　　$date_time_array = getdate ( $date );

　　$hours = $date_time_array [ "hours" ];

　　$minutes = $date_time_array [ "minutes" ];

　　$seconds = $date_time_array [ "seconds" ];

　　$month = $date_time_array [ "mon" ];

　　$day = $date_time_array [ "mday" ];

　　$year = $date_time_array [ "year" ];

　　switch ( $interval ) {

　　case "yyyy" : $year += $number ; break ;

　　case "q" : $month +=( $number *3); break ;

　　case "m" : $month += $number ; break ;

　　case "y" :

　　case "d" :

　　case "w" : $day += $number ; break ;

　　case "ww" : $day +=( $number *7); break ;

　　case "h" : $hours += $number ; break ;

　　case "n" : $minutes += $number ; break ;

　　case "s" : $seconds += $number ; break ;

　　}

　　$timestamp = mktime ( $hours , $minutes , $seconds , $month , $day , $year );

　　return $timestamp ;

　　}

　　function DateDiff ( $interval , $date1 , $date2 ) {

　　$timedifference = $date2 - $date1 ;

　　switch ( $interval ) {

　　case "w" : $retval = bcdiv ( $timedifference ,604800); break ;

　　case "d" : $retval = bcdiv ( $timedifference ,86400); break ;

　　case "h" : $retval = bcdiv ( $timedifference ,3600); break ;

　　case "n" : $retval = bcdiv ( $timedifference ,60); break ;

　　case "s" : $retval = $timedifference ; break ;

　　}

　　return $retval ;

　　}

　　}

　　?>