W3C home > Mailing lists > Public > public-html@w3.org > September 2007

Re: Use cases for a few elements: event-source, details, datagrid, datalist, menu, and command

From: Lachlan Hunt <lachlan.hunt@lachy.id.au>
Date: Thu, 06 Sep 2007 18:52:45 +1000
Message-ID: <46DFBFDD.805@lachy.id.au>
To: Robert Burns <rob@robburns.com>
CC: public-html <public-html@w3.org>

Robert Burns wrote:
> there are several elements that I 
> haven't been able to get my mind around just from the draft or reading 
> the discussions on this list. So to help me — and presumably other 
> members — I'd like to start some discussion of those elements. Perhaps 
> this thread should immediately fork into element-specific threads. Feel 
> free to do so.
> 
> DATALIST [5]
> -------------------------
> The datalist element also looks very much like a select element, though 
> with a slightly different presentational UI. Is this something that 
> would be better handled through CSS? If not, why not?

This provides the ability to markup combo boxes, where the user can 
either select a predefined value or type their own.  These are quite 
often simulated using various JavaScript and CSS techniques, with 
varying degrees of success.  Datalist makes it significantly easier for 
authors to use combo boxes and allows UAs to provide more consistent 
interfaces.

Use cases:

* Many web sites that ask users for personal information often ask for 
their title and typically provide a few default options like Mr, Mrs, 
Ms, etc.  But there are many people who would prefer to use, for 
example, Dr, Capt, etc. and its impractical to list every possibility in 
a single list.  Many sites implement this by providing an "Other" option 
in the list and an additional text box nearby for the user to enter it.

* Surveys often ask users questions and provide a set of the most common 
options for the user to select.  e.g. "How did you find this site?" is a 
fairly common question, with answers like "Search Engine", 
"Advertisement", "Referral from a friend", etc.  Such questions usually 
also provide an "Other" field for the user to provide a different response.

I use a datalist on my own "Echo Content" tool for selecting or entering 
MIME types.  I list the most common ones in the list for convenience and 
allow users to enter any other they wish.  It uses a <select> with 
JavaScript as a fallback in browsers that don't support <datalist>.  You 
can try it out in Opera, which has an early implementation of it 
already.  The list will display when the text box has focus.

http://html5.lachy.id.au/output

> EVENT-SOURCE [6]
> -------------------------
> For this element, I had great difficulty in deciphering the use cases 
> for it. Any discussion on this would be helpful.

In addition to the use cases Chaals provided for this, there are a few 
other applications that would benefit from its use.

* Web mail applications could use the events to instantly notify users
   of new emails without having to reload the page.
* Web based Instant Messaging (e.g. Google Talk, which is built into
   GMail or Twitter's web interface).
* Interactive web based games. e.g. Events could be used to notify
   players of another users move.

-- 
Lachlan Hunt
http://lachy.id.au/
Received on Thursday, 6 September 2007 08:52:59 UTC

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