php 留言板防刷新

     
      php 留言板防刷新效果
      $ip = $_SERVER['REMOTE_ADDR'];
      $conn = mysql_connect($mysql_server_name, $mysql_username, $mysql_password);
      $sql = "SELECT * FROM `my_counter` WHERE ip = '$ip'";
      mysql_select_db($mysql_database, $conn);
      $result = mysql_query($sql);
      $row = mysql_fetch_row($result);
      print_r($row);
     
      if(!$row)   //如果IP没有出现过就新增
      {
       $sql = "INSERT INTO `my_counter` ( `new`, `ip`, `time_at`) VALUES ('1', '$ip', NOW())";
       $result = mysql_query($sql);
      }
      else        //如果IP出现过
      {
       $sql = "SELECT TIME_TO_SEC( NOW( ) ) - TIME_TO_SEC( time_at ) FROM `my_counter` WHERE `ip` = '$ip'ORDER BY `TIME_TO_SEC( NOW( ) ) - TIME_TO_SEC( time_at )` ASC ";
       $result = mysql_query($sql);
       $row = mysql_fetch_row($result);
       print_r($row);
      
       if($row[0]>5)   //如果IP出现过，则看他有没有超过5秒
       {
         $sql = "INSERT INTO `my_counter` ( `new`, `ip`, `time_at`) VALUES ('1', '$ip', NOW())";
         $result = mysql_query($sql);
       }
      }
     
       $sql = "SELECT COUNT(*) FROM `my_counter`";
       $result = mysql_query($sql);
       $row = mysql_fetch_row($result);
       print_r($row);
       mysql_free_result($result);
       mysql_close($conn);
?>