使用php清除bom示例

       global $auto; 

       $contents = file_get_contents($filename); 

        $charset[1] = substr($contents, 0, 1); 

       $charset[2] = substr($contents, 1, 1); 

       $charset[3] = substr($contents, 2, 1); 

       if (ord($charset[1]) == 239 && ord($charset[2]) == 187 && ord($charset[3]) == 191) { 

           if ($auto == 1) { 

              $rest = substr($contents, 3); 

              rewrite ($filename, $rest); 

              return ("<font color=red>BOM found, automatically removed.</font>"); 

           }else { 

              return ("<font color=red>BOM found.</font>"); 

           } 

       }else return ("BOM Not Found."); 

    }