#!/usr/bin/perl -w

use strict;
my ($tagOpen, $tagClosed, $parseData);

open(FILE, "<", 'htmlFile.html') || 
   die "Error reading file: ($!)\n";
$parseData .= $_."\n" while (<FILE>);
close(FILE);

my @tags = qw(TITLE AUTHOR H1 H2 P IT);
for (@tags) {
   $tagOpen++   while ($parseData =~ /<$_>/g);
   $tagClosed++ while ($parseData =~ /<\/$_>/g);
   error($_, $tagOpen, $tagClosed) unless ($tagOpen == $tagClosed);
   $tagOpen = $tagClosed = 0;
}

sub error {
   my ($tag, $open, $closed) = @_;
   print "Error found in tag: <$tag> (Open: $open -- Closed: $closed)\n";
   return;
}