PHP简单实现文本计数器的方法

<?php
  if (file_exists('count_file.txt'))
  {
    $fil = fopen('count_file.txt', r);
    $dat = fread($fil, filesize('count_file.txt'));
    echo $dat+1;
    fclose($fil);
    $fil = fopen('count_file.txt', w);
    fwrite($fil, $dat+1);
  }
  else
  {
    $fil = fopen('count_file.txt', w);
    fwrite($fil, 1);
    echo '1';
    fclose($fil);
  }
?>