A little bit off topic to the HTML::FillInForm discussion (or maybe not).

But does anyone know of a module like HTML::FiF that would allow me to
fill in other things such as: 

    <span id='error_firstname'></span>

So that if I had a static HTML file with a form on it, I could place
the error message place holder right where I wanted them at the time
that I write the HTML and only activate them on submit by re-reading
the .html file and then using HTML::FiF to fill in the form AND the
appropriate Fill-In other module to fill in the empty <spans> with the
error messages and then return the entire output to the user. 

I'm about on the edge of rolling my own in a fashion similar to
HTML::FillInForm, but thought I would check first. (Otherwise, I might
roll out HTML::FillInAnything) 

I do understand that:

a) The concept for this module would be moot if I was generating the
form dynamically from a template that could include [% error_firstname
%] tags. Which I'm not. But in respect, what I'm looking for is also
cleaner than the syntax of <input type='text' name='firstname'
value='[% firstname %]'>, which is what we'd be left with if we didn't
have HTML::FiF in the first place. 

b) I could probably do something like
<span><!--error_firstname--></span> and have the entire file re-parsed
by TT using HTML comment tags as my start / end tags, but I think the
fill in approach would still be cleaner.