John M. Dlugosz:

If you want to give the users some ability to format the text, perhaps using one of the WIKI text modules (such as Text::Markup::Mediawiki) may be a solution. That way, the module will generate the HTML, rather than the users. The HTML would then be generated properly (I would hope!), and the user would get a simple mechanism to format their posts.

...roboticus

When your only tool is a hammer, all problems look like your thumb.