use HTML::TagReader;
  my $filename = 'test2.html'; # Here instead of using this file I want to do same thing using HTML as a string in some variable say $html_string = 'content of test2.html'
  my $p=new HTML::TagReader "$filename";
    open(my $fh, '<', $filename) or die "Could not open file '$filename' $!";
  my %line_chars;
  my $line_number = 1;
  while (my $row = <$fh>) {
        if ($line_number > 1) {
              $line_chars{$line_number} =  $line_chars{$line_number - 1} + length($row);
        } 
        else {
              $line_chars{$line_number} =  length($row);
        }
        $line_number++;
  }
  my @atags;
  my %atagrange;
  while(my ($tagOrText,$tagtype,$linenumber,$column)=$p->getbytoken($showerr)) {
        my $position;
        my $a_start_tag_pos;
        if ($linenumber > 1) {
              $position = $line_chars{$linenumber - 1} + $column;
      }#print "\ntagOrText:" . $tagOrText . "\ntagtype : " . $tagtype . "\nline number :" .  $linenumber . "\ncolumn : " . $column . "\nposition : " . $position . "\n";
        if ($tagtype eq "a" or $tagtype eq '/a') {
              if ($tagtype eq "a") {
                    push(@atags, $position);
              } 
              else {
                    $a_start_tag_pos = pop(@atags);
                    $atagrange{$a_start_tag_pos} = $position;
              }
        }
  }