What is to be named after printing HTML?

Hello experts,
What should you name after printing HTML? It should be print from a Perl CGI script.
Also, I have noticed an empty return reports, exit reports, and in a number of cases.
Does it issue?
#!perl
print "Content-type: text/htmlnn";
print <<'END_HTML';
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Hello world!</title>
</head>
<body>
<h1>Hello world!</h1>
</body>
</html>
END_HTML
# do anything else here?
# return;
# exit;
I need to solve it. Please help. Thanks.
