There is always a TIMTOWTDI.

Consider something like illustrated in this simple but very instructive example from the friendly manual of HTML::HTML5::Builder by tobyink:

use HTML::HTML5::Builder qw[:standard JQUERY];
 
open my $fh, '<', 'inline-script.js';
 
print html(
  -lang => 'en',
  head(
    title('Test'),
    Meta(-charset => 'utf-8'),
  ),
  body(
    h1('Test'),
    p('This is a test.'),
    JQUERY(-version => '1.6.4'),
    script(-type => 'text/javascript', $fh),
  ),
);
[download]

For an example of total abuse of Plack see Re^3: How do I run a loop within a PSGI application. See also Re^3: RFC: Proofread the POD for my HTML elements module, PSGI and Plack.