解析PHP计算页面执行时间的实现代码

如下所示：

<?php 
 $t = new executeTime; 
 phpinfo(); 
 class executeTime{ 
     private $microtime; 
     public function __construct(){ 
         $this->microtime = microtime(true); 
     }          public function getNow(){ 
                 $this->__dectruct(); 
         } 
     public function __destruct(){ 
         if (empty($_SERVER['REQUEST_TIME_FLOAT'])) 
             echo '<div style="color:#fff;background:#000;position:absolute;top:0px;right:0px;padding:3px 6px;">本次执行时间：', microtime(TRUE) - $this->microtime, '秒</div>'; 
         else 
             echo '<div style="color:#fff;background:#000;position:absolute;top:0px;right:0px;padding:3px 6px;">本次执行时间：', microtime(TRUE) - $_SERVER['REQUEST_TIME_FLOAT'], '秒</div>'; 
     } 
 }