[mdlug] User agent strings

[Robert Meier]

Drew,

> I heard a rumor that it's possible to get *any* browser to send
> a different userAgent string than its default either by appending a
> '?' and a variable assignment, or by means of a script of some sort.
> Can anyone confirm this and show exactly how?

My understanding is that http (hypertext transport protocol) supports
upload of key-value pairs by two methods, get and post.
The get method appends the key-value pairs to the URL delimited by
    ? after the url path and before the key-value pairs
    & between key-value pairs
    = after each key and before each value
The post method sends a multi-line file, that includes key-value pairs
one per line.

A browser can use select either get or post method,
and the server may choose to accept either or both.

Appending '?userAgent="string"' to a path-only url
(or '&userAgent="string" to a url with other key-value pairs)
utilizes the get method.
If the server accepts the userAgent value by get method,
I would expect this to work.

Get method becomes inefficient as the key-value pair count rises,
so filled-in forms are usually uploaded by post method.
I know of no easy way to add key-value pairs to upload by post method.
If the server accepts or overrides the userAgent value by posts method,
I would expect this to problematic.

Hopefully helpful,
-- 
Dr. Robert J. Meier