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Why firefox is not sending 'filename' parameter for form file parts encoded as specified in rfc2388?


rfc2388 states:

The original local file name may be supplied as well, either as a "filename" parameter either of the "content-disposition: form-data" header or, in the case of multiple files, in a "content-disposition: file" header of the subpart. The sending application MAY supply a file name; if the file name of the sender's operating system is not in US-ASCII, the file name might be approximated, or encoded using the method of RFC 2231.

But firefox is just sending 'filename' parameter encoded with the page encoding or the form accept-charset, this is, it is sending raw UTF-8 or the choosen encoding.

Which is the reason for this?

Additional System Details


  • User Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.152 Safari/537.22

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251 solutions 3018 answers


Thank you for inquiring about your issue on Mozilla Support! We appreciate your patience while we find an answer to your issue. At this moment I am escalating this to our advanced troubleshooting team who will assist you further in 24-48 hours.

Thank You!

Best Regards,


  • Top 25 Contributor
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191 solutions 1967 answers

It would help answer your question if you could describe the issue better and how it is affecting your use of Firefox. For example, is the problem related to the following?

If you are not having a specific issue with using Firefox, you can

Here is a list of bugs with a comment mentioning rfc2388, in case it helps ... and here is another list of bugs mentioning rfc 2388 (with a space).

P.S. Before filing a bug report or adding a comment to a bug, please read https://developer.mozilla.org/en-US/docs/Mozilla/QA/Bug_writing_guidelines and https://bugzilla.mozilla.org/page.cgi?id=etiquette.html

Modified by AliceWyman

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10753 solutions 96760 answers

If this is about your own website then try to ask advice at the MozillaZine "Web Development/Standards Evangelism" forum.

The helpers at that forum are more knowledgeable about web development issues.
You need to register at the MozillaZine forum site in order to post at that forum.