Re: Client-side highlighting; tag proposal

Joe English (jenglish@crl.com)
Fri, 10 Mar 1995 10:49:21 -0800


Message-Id: <199503101849.AA07198@mail.crl.com>
To: Multiple recipients of list <www-html@www10.w3.org>
Subject: Re: Client-side highlighting; tag proposal 
In-Reply-To: <ab8564ae04021004a16a@[192.187.143.12]> 
Date: Fri, 10 Mar 1995 10:49:21 -0800
From: Joe English <jenglish@crl.com>


narnett@verity.com (Nick Arnett) wrote:

> A couple of times lately, I've brought up the notion that clients should
> handle highlights (the terms that match a search query) better.  It's
> rather inefficient to force the search server to proxy documents just so
> that it can add highlights.  Worse, it takes the decision about *how* to
> highlight (bold?  underline?  surround with asterisks?) out of the user's
> hands (barring some sort of ugly protocol for telling the server).
> 
> We'd like to suggest a very simple approach -- a highlight tag. [...]
>
> I'd like to hear (1) suggestions on the form of this tag (we're assuming
> something terribly simple such as <hl> and </hl>) and (2) objections or
> concerns.

The current HTML3 draft has a <MARK> element that would
work well for this.

<MARK> is an EMPTY element, used in pairs to mark 
contiguous spans of the document that may cross element
boundaries:

    <!ELEMENT MARK - O EMPTY>
    <!ATTLIST MARK -- requires either start or end attribute --
	    class   NAMES   #IMPLIED   -- used to subclass range --
	    start   ID      #IMPLIED   -- defines name of range --
	    end     IDREF   #IMPLIED   -- paired with start element --
	    >

<MARK> elements may appear anywhere that character data
is legal [*].  This would work perfectly for a search application --
it could insert <MARK class=highlight start=xxx> at the start
of each range and <MARK end=xxx> at the end, without having
to worry about the element hierarchy.  <HL> ... </HL> wouldn't 
work in all cases.

([*] well, almost anywhere.  To Dave Raggett: MARK should be added 
to %pre.content; and a few other places where it's not currently legal.  
Just making it an inclusion exception might mess up record-end
processing; I'll investigate that.)



--Joe English

  jenglish@crl.com