function download_file($file,$showname){

if(is_file($file)){

$length = filesize($file);

$type = mime_content_type($file);

header("Content-Description: File Transfer");

header('Content-type: ' . $type);

header('Content-Length:' . $length);

if (preg_match('/MSIE/', $_SERVER['HTTP_USER_AGENT'])) {

header('Content-Disposition: attachment; filename="' . rawurlencode($showname) . '"');

} else {

header('Content-Disposition: attachment; filename="' . $showname . '"');

}

readfile($file);

exit;

} else {

exit('文件已被删除！');

}

}