Tk is a GUI toolkit, not a web based framework. My suggestion is that you have one script (main.pl for argument sake) which displays your user interface (learn about HTML/CSS/JavaScript). I'd advise against embedding the HTML etc within your perl script. Consider using HTML::Template (or Template::Toolkit).

Your example Tk program doesn't do much. You could easily replace it with an HTML user interface using advice in links you've already been given.