print "Content-Type: text/html\n\n";

##</code><code>##

  print header();

##</code><code>##

  binmode(STDOUT);
  $html = ...;
  print "Content-Type: text/html\r\n",
        "Content-Length: ", length($html), "\r\n\r\n",
        $html;

##</code><code>##

  $html = ...;
  print header(-content_length => length($html)), $html;