For a form with a single form element, Perl will automatically
generate a hidden submit button that will respond to the carriage
return.
If there is only one submit button on a page (for example a page
with multiple forms), it will automatically respond to the carriage
return. If there is more then one submit button on the page, it must
be manually clicked.
When a submit button is invoked, the data on the form is
submitted to the web server.
The Perl CGI construct to create a submit button would be as
follows:
# Generate a submit button for this form
print $query->submit();