使用php清除bom示例

function checkBOM ($filename) {     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.");   }

ob_get_clean();ob_clean();header("Content-type: image/jpeg");