What you say may be true, as I have heard this from
more than one source. Seems that Web Browsers use
the "<!" and the next ">" to delimit comments, and
do not follow the convention you mention. This can
be tested with things like:
"<! this ---- is -- a -- test -->"
or
"<!-- this is a test>"
where you will see that example 1 and 2 "browses" OK.
The "dashes" are ignored! Browsers look for ONLY the
beginning "<!" and the ending ">" and that's all.
-JB
Marvin Simkin wrote:
>
> Although it is not widely known (and web page authors break this routinely)
> two dashes begins a comment and another two dashes ends it. So you can switch
> back and forth several times in a single tag:
>
> <!--comment--livestuff--comment--livestuff--comment...
>
> As far as I know actual use of this "feature" is quite rare. So I ended up
> coding my parser to actual use rather than to spec. I suspect the folks that
> write web browsers do the same thing more often than they "should".
>
> Parsing HTML is hard enough. Parsing garbage reliably -- and matching other
> people's undocumented parsers and undocumented language elements -- is nearly
> impossible.
>
> From: JRB%w3f.com@Internet on 2000-03-07 04:32 PM
> To: kero%3sheep.com@Internet
> cc: libwww%perl.org@Internet (bcc: Marvin Simkin)
> Subject: Re: patch for HTML::Parser 3.06 to fix declaration
> commenthandling
>
> Why not just look for "-->" to end it?
> -JB
>
> la mouton wrote:
> >
> > This fixes a bug in declaration handling. HTML::Parser supports comments
> > within declarations (<! foo -- comment -->) incorrectly. Once we trigger
> > a comment "--" we look for the next instance of "--" to denote the end of
> > the comment. I put in a check for the end of tag character '>', otherwise
> > we dont get out of comment mode before the appearance of another "--"
> > marker.
> >
> > -f
> >
> > diff -u -r HTML-Parser-3.06/hparser.c HTML-Parser-3.06.fixed/hparser.c
> > --- HTML-Parser-3.06/hparser.c Mon Mar 6 08:30:13 2000
> > +++ HTML-Parser-3.06.fixed/hparser.c Tue Mar 7 11:24:54 2000
> > @@ -792,8 +792,10 @@
> > s++;
> >
> > while (1) {
> > - while (s < end && *s != '-')
> > + while (s < end && *s != '-' && *s != '>')
> > s++;
> > + if (*s == '>')
> > + goto DONE;
> > if (s == end)
> > goto PREMATURE;
> > s++;
> > @@ -824,7 +826,8 @@
> > if (s == end)
> > goto PREMATURE;
> > if (*s == '>') {
> > - s++;
> > + DONE:
> > + s++;
> > report_event(p_state, E_DECLARATION, beg, s, tokens, num_tokens,
> > offset, self);
> > FREE_TOKENS;
