生成的xml文件对计算机有害吗？

I did an xml file and force download it by these headers:

header('Content-disposition: attachment; filename="export.xml"');
header('Content-type: application/xml; charset=utf8');
readfile('export.xml');

But before the download I see a dialog that this file can be harmful for my computer? How to get rid of this dialog? Maybe my headers is wrong?

upd Well, can do nothing, I did a test on my test-hosting, u can check it here: site with generation link, and an xml file as is: export.xml

Try changing application/xml to text/xml. Probably your browser thinks that application means executable.

Try this :

<?php 
header('Content-disposition: attachment; filename="export.xml"');
header('Content-type: "text/xml"; charset="utf8"');
readfile('export.xml');
?>

Note: This does not solve your issue, however it did solve an issue I had on my computer giving that notice (windows, chrome, apache webserver, PHP 5.4.10). I leave it here for future visitors.

Some browsers do not only look for the headers but also for the "filename" in the URL.

For example if you download a PHP file that contains XML, the browser might identify it as a dangerous file (because it can be executed on your system or is not within some whitelist or what not):

http://example.com/xml-download.php

A simple solution is to make this file not end with .php any longer, for example by adding a ?:

http://example.com/xml-download.php?

And continue with that to even signal the filename that way:

http://example.com/xml-download.php?export.xml

(the last one is not necessary but can be useful especially with some older browsers)