As per Relevance of the word september, we have this rfc below:
Network Working Group D.
Request for Comments: 2936
Category: Informational C.
Royal Bank of
D.
September 2000
HTTP MIME Type Handler
Status of this
This memo provides information for the Internet community. It
not specify an Internet standard of any kind. Distribution of
memo is unlimited
Copyright
Copyright (C) The Internet Society (2000). All Rights Reserved
Entities composing web pages to provide services over the
Transfer Protocol (HTTP) frequently have the problem of not
what Multipurpose Internet Mail Extensions (MIME) types have
installed at a user's browser. For example, whether an Internet
Trading Protocol (IOTP) or VRML or SET or some streaming
handler is available. In some cases they would want to
different web pages or content depending on a MIME handler'
availability. This document summarizes reasonable techniques
solve this problem for most of the browsers actually deployed on
Internet as of early 2000. It is intended to be of practical use
implementors during the period before the wide deployment of
standards based techniques which may be developed
Helpful comments by Tony Lewis of Visa have been incorporated
Eastlake, et al. Informational [Page 1]
RFC 2936 HTTP MIME Type Handler Detection September 2000
Table of
1. Introduction................................................. 2
2. The HTTP 'Accept' Header..................................... 2
3. JavaScript................................................... 3
4. ActiveX and the Windows Registry............................. 4
5. ECML, The Electronic Commerce Modeling Language.............. 4
6. Putting It All Together...................................... 5
7. Future Development........................................... 5
8. Security Considerations...................................... 5
9. IANA Considerations.......................................... 6
References...................................................... 6
Appendix A: Browser Version Sniffer Code........................ 8
Authors' Addresses.............................................. 12
Full Copyright Statement........................................ 13
1.
Entities composing web pages to provide services over [HTTP
frequently have the problem of not knowing what [MIME] types
handlers installed at a user's browser. For example, whether
[IOTP] or VRML or [SET] or some streaming media handler is available
In many cases they would want to display different web pages
content depending on a MIME handler's availability. Sending
response with a MIME type that is not supported frequently results
interrupting the flow of the user experience, browser queries as
what to do with the data being provided, and, of course, failure
provide the behavior that would have occurred had the correct
type handler been installed
This document describes reasonable techniques to solve this
for most of the browsers actually deployed on the Internet as
early 2000. It is intended to be of practical use to
during the period before the wide deployment of superior
based techniques which may be developed. It is written in terms
determining whether a handler for application/iotp or application/x
iotp exists but is equally applicable to other MIME types
2. The HTTP 'Accept'
The problem should be solved by the Hyper Text Transport
[HTTP] request "Accept" header which lists accepted [MIME] types
This header is present in both Version 1.0 and 1.1 of HTTP and
content is supposed to be a list of MIME types and subtypes that
accepted. The only problem is that many browsers just send "*/*"
the like
Eastlake, et al. Informational [Page 2]
RFC 2936 HTTP MIME Type Handler Detection September 2000
If the particular MIME type you are looking for is
present in the Accept header, it is generally safe to assume that
handler for it is actually installed or part of the browser
NOTE: Although not part of the main topic of this document, if
are designing MIME type handler software and have access to a
interface that allows you to request the insertion of the MIME
or types your software handles into the Accept header, you
should do so. It will make it easier for servers sensitive to
MIME type to respond correctly
3.
Most recent browsers support one or more scripting languages of
the most widely deployed is "JavaScript". These scripting
appear in web pages and permit the interpretive execution
programming language constructs that can probe the
environment, conditionally cause different page contents to
displayed, etc. For example, Appendix A shows JavaScript
from the Netscape web site for determining what operating system
browser, and version on which a web page is appearing
NOTE: JavaScript is a trademark of SUN Microsystems, Inc. It
originally called LiveScript. It has nothing to do with the
language
The syntax for script use appears to be a Hyper Text Markup
(HTML) comment so that browsers that do not support scripting
ignore such items. That is, script use is preceded by "". The following is a simple example
conditional execution of parts of a web page based on JavaScript
type handler detection
