PHP 计算页面执行时间

<?php
class runtime
{
    var $StartTime = 0;
    var $StopTime = 0;
 
    function get_microtime()
    {
        list($usec, $sec) = explode('' '', microtime());
        return ((float)$usec + (float)$sec);
    }
 
    function start()
    {
        $this->StartTime = $this->get_microtime();
    }
 
    function stop()
    {
        $this->StopTime = $this->get_microtime();
    }
 
    function spent()
    {
        return round(($this->StopTime - $this->StartTime) * 1000, 1);
    }
 
}
 
 
//例子
$runtime= new runtime;
$runtime->start();
 
//你的代码开始
 
$a = 0;
for($i=0; $i<1000000; $i++)
{
    $a += $i;
}
 
//你的代码结束
 
$runtime->stop();
echo "页面执行时间: ".$runtime->spent()." 毫秒";
 
?>