Feedback wanted: wrapping long lines in HTML docs

[Warren Block]

HTML versions of our documents show long lines in <screen> and 
<programlisting> elements.  At present, these  lines run right out of 
the boxes they are in.  Some lines are very long.  An example in the FDP 
Primer is 473 characters:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/fdp-primer/xml-primer-elements.html
(search for "example.xml:5")

We have at least two ways of improving this.  Long lines can be treated 
as they are in the PDF versions: the line is wrapped and an indicator 
character shows where it has been wrapped.  Cut and paste will still 
copy it as a single line.  Advantage: the entire contents of long lines 
are shown.  Disadvantage: readers may misunderstand the wrapping or wrap 
indicator as literal.

Another option is to add "overflow: auto" in the CSS.  Scroll bars will 
be added to the bottom of screen and programlisting elements with long 
lines.  Advantage: long lines are shown without wrapping. 
Disadvantage: the reader has to scroll to see the hidden part of long 
lines.


Which method should be preferred for HTML documents, and why?