php 在客户端生成txt文件并且下载

　　$filename = 'file.text'; //也可以是其他后缀格式的
$ua = $_SERVER["HTTP_USER_AGENT"];
foreach ($fedexinfo as $key => $value) {
echo $key.",\"".$value."\"\r\n";
}
header("Content-Type: application/octet-stream");
header('Content-Disposition: attachment; filename="' .  $filename . '"');