Using fileReference.upload as3 will cause an error in Firefox.

Just like the title, it is said on the Internet that the sessionid is empty and the sessionid needs to be passed through the URL. How should the URL be written?
I tried changing the URLRequest to http://localhost/file.php?phpsessid=test, and added session_id($_POST['phpsessid']);session_start(); to the file.php file on the server; the result is still the same No, what can I do?

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Just like the title, it is said on the Internet that the sessionid is empty and the sessionid needs to be passed through the URL. How should the URL be written?
I tried changing the URLRequest to http://localhost/file.php?phpsessid=test, and added session_id($_POST['phpsessid']);session_start(); to the file.php file on the server; the result is still the same No, what can I do?

An article I wrote before, please check if it is helpful to you. Summary of 302 errors in uploadify in PHP framework

i don't know what is the problem,i give up,it dosen't matter to me now.Maybe it was the php_ini block the url sending sessionid to server.