这有一个测试页面执行时间的类

<?php
/**
 * @功能：PHP计时器类
 * @参数：null
 * @返回：string
**/
function timer()
{
$timer = new timer();
$timer->start();
sleep(1);
$timer->stop();
return $timer->show();
}
class timer
{
    var $time_start;
    var $time_end;
    function __construct()
    {
       $this->time_start = 0;
       $this->time_end = 0;
    }
    function timer()
    { 
       $this->__construct();
    }
    function start()
    { 
       list($usec,$sec) = explode(" ",microtime());
       $this->time_start = (float)$usec + (float)$sec;
    }
    function stop()
    { 
       list($usec,$sec) = explode(" ",microtime());
       $this->time_end = (float)$usec + (float)$sec;
    }
    function show($output = false)
    {
       $total = $this->time_end - $this->time_start;
if($output)
{ 
echo $total," sec";
return true;
} 
return $total." sec";
    }
}
?>