php计算页面执行时间

StartTime = microtime();}
function stop(){
$this->StopTime　= microtime();}
function spent(){
if ($this->TimeSpent) {
return $this->TimeSpent;
} else {
$StartMicro = substr($this->StartTime,0,10);
$StartSecond = substr($this->StartTime,11,10);
$StopMicro　 = substr($this->StopTime,0,10);
$StopSecond　= substr($this->StopTime,11,10);
$start = doubleval($StartMicro) + $StartSecond;
$stop　= doubleval($StopMicro) + $StopSecond;
$this->TimeSpent = $stop - $start;
return substr($this->TimeSpent,0,8)."秒";
}
}// end function spent();
}//end class timer;
//例子
$timer = new timer;
$timer->start();
/*
你的代码放在此处
*/
$timer->stop();
echo "执行本SCRIPT共".$timer->spent();
?>