I can easily reproduce this on firefox 3.0.11 too.
I'll try and sent you a pm with an attached htm file that is a straight View Source > Save of a page with the offending code. To open the file, go File > Open in firefox and see what happens.
Probably other browsers will do the same. I haven't checked widely.
I think you need to re-check the HTML code parsing routine you are using to ensure that no active <script> tags remain in the code you display here.