Content Disposition in different browsers

Today I had to resolve an issue where in different browsers the filed dynamically generated download worked very differently / at all

The setup, we had an xml file with a custom extension, say .mj, which was being served up by ASP. The HTTP Header had a content disposition header and a response type set.

Response.AddHeader "Content-Disposition", "attachment; filename=""our file.mj"""
Response.ContentType = "text/xml"

This worked fine in Internet Explorer, the file was downloaded as "our file.mj". However FireFox and Chrome acted very differently, in FireFox the file was downloaded as just "our", and Chrome as "our file.xml".

In FireFox it appears that the issue is caused by having a space in the file name, this forum post by funkdaddu helped me on this, so by removing the space FireFox could now download the file as "ourfile.mj".

Chrome however did not want to play ball. It was still insisting on changing the file extension to ".xml". I guessed it was because we were telling it we serving up text/xml mime/type under a different file extension, I decided to change the response type to "Application/Save" just to see if this would make a difference, and amazingly it did. Amazing!

So there we have it, changing the file name to have no spaces and ensuring that the content type is set to "Application/Save" seems to make all browsers behave at least some what consistently with the Content Disposition header. Its worth noting that Scott Hanselman has a great blog post The Content Disposition Saga which talks alot about how the different of IE handles it. Also GreenBytes has a ton Test Cases for HTTP Content-Disposition header which I certainly found helpful.