隐性调用php程序的方法

调用方法：
<script language = "javascript" src = "count.php"></script>
count.php源码：

<?php 
$file_name = "count.txt"; 
$fp = fopen($file_name,"r"); //打开文件读入当前计数 
$count = fread($fp, filesize($file_name)); 
fclose($fp); 
$count++; //计数加1 
$fp = fopen($file_name, "w"); //再次打开文件写入更新后的计数 
fwrite($fp, $count); 
fclose($fp); 
echo "document.write('".$count."')"; //输出JavaScript代码，返回计数 
?>