统计php程序运行时间

<?php  $pagestartime=microtime();?><?php 程序段?><?php  $pageendtime = microtime();  echo $pageendtime."<br/>";  $starttime = explode(" ",$pagestartime);  $endtime = explode(" ",$pageendtime);  $totaltime = $endtime[0]-$starttime[0]+$endtime[1]-$starttime[1];  $timecost = sprintf("%s",$totaltime);  echo "页面运行时间: $timecost 秒";?>