Yes, you want:

  s/\Q$complete\E/...
[download]

because $complete has metacharacters in it. Pretty much any time you want to stick a variable in a regex, you want to use \Q...\E. The only exception is if the variable is supposed to contain a regex itself, but that can get dangerous (arbitrary perl code in regexes, etc).

Also, maybe Template::Toolkit would be of use. It just does general text templates, making no assumptions about web apps or HTML.