php时间调用有关问题

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><?php   function format_time($time){       $t=time()-$time;       $f=array(           '31536000'=>'年',           '2592000'=>'个月',           '604800'=>'星期',           '86400'=>'天',           '3600'=>'小时',           '60'=>'分钟',           '1'=>'秒'      );         foreach ($f as $k=>$v)       {                   if (0 != $c=floor($t/(int)$k))           {               return $c.$v.'前';           }       }   }   echo format_time('1336880454');   ?>

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><?php $time1 = "2012-05-13 11:40:54";$time2 = strtotime($time1);echo $time2;//转换成时间戳格式echo date('',$time2);//转换成标准日期格式?>

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><?php while ($row = mysql_fetch_array($rs_tmmsm)) {?><?=date("Y-m-d <!--h:i-->",strtotime($row["pay_time"]))?><?php }?>

<?php function format_time($time){       $t=time()-$time;       $f=array(           '31536000'=>'年',           '2592000'=&gt;'个月',           '604800'=&gt;'星期',           '86400'=&gt;'天',           '3600'=&gt;'小时',           '60'=&gt;'分钟',           '1'=&gt;'秒'      );         foreach ($f as $k=&gt;$v)       {                   if (0 != $c=floor($t/(int)$k))           {               return $c.$v.'前';           }       }   }  while ($row = mysql_fetch_array($rs_tmmsm)) {    echo format_time(strtotime($row["pay_time"]));}?&gt;<div class="clear"></div>