Value of Content-Disposition header:
Content-Disposition: attachment; filename=foo.html, attachment; filename=bar.html
Test Description:
'attachment', two comma-separated instances of the header field. As Content-Disposition doesn't use a list-style syntax, this is invalid syntax and, according to RFC 2616, Section 4.2, roughly equivalent to having two separate header field instances.
This is invalid, so UAs should ignore it.