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Re: Server-side image maps definition?

for

From: Jukka K. Korpela
Date: Aug 30, 2005 10:40AM

On Mon, 29 Aug 2005, Patrick H. Lauke wrote:

> Hoffman, Allen wrote:
>> I read that looking for "input type"image" indicates an image map is on
>> a page. M ai missing something, or is this inaccurate.
>
> input type="image" does not necessarily indicate a (server-side) image map.

It depends on how you define "(server-side) image map". It is certainly
true that the program code on the server that processes the form data
may completely ignore the x and y coordinates - just as it can if you have
used <img ... ismap> in HTML.

> Yes, when clicked with the mouse the browser submits the current form and
> passes on X and Y coordinates...

Correct.

> something which can't be done via the
> keyboard or alternative input devices.

Well, browsers just don't support alternative devices - and admittedly it
would be difficult to react e.g. to the user's eye movements; it would
surely be possible with the current state of the art, but it would require
suitable hardware and software.

> However, many times image inputs are
> simply used as graphical submit buttons, where X and Y are actually
> irrelevant and there's no special behaviour depending on where a user
> clicked.

That's probably much more common than using the x and y values.

> In that situation, they can actually work for keyboard users as
> well...

Not as well. Image submit buttons have several problems; most of them are
probably described at
http://www.cs.tut.fi/~jkorpela/forms/imagebutton.html
To begin with, the very reason for using image submit buttons (authors
want to make their buttons look cool) is a strong reason for _not_ using
them, even if we ignore the technical difficulties. If it's a button, it
should look like a button.

> it just submits the form, but doesn't pass any X and Y.

It typically passes x=0&y=0 (which is theoretically inadequate but
manageable in practice).

--
Jukka "Yucca" Korpela, http://www.cs.tut.fi/~jkorpela/