Have a look at $h->splice_content(...).

The cut down example below inserts new text immediately after the opening div tag (if a text element is not found). 

#!/usr/local/bin/perl

use strict;
use warnings;
use HTML::TreeBuilder;

my $html = do{local $/;<DATA>};
my $replace = q{replaced};
my $edited = edit($html, $replace);
print $edited;

sub edit{
  my $html = shift;
  my $replace = shift;
  
# my $root = HTML::TreeBuilder->new_from_file($html_file)
#   or die qq{cant build tree\n}; 

  my $root = HTML::TreeBuilder->new_from_content($html)
    or die qq{cant build tree\n}; 

  my $class3 = $root->look_down(
    _tag  => q{div}, 
    class => q{class3},
  );
  die qq{class3 not found\n} unless $class3;

  my $rep_class3;
  for my $item_r ($class3->content_refs_list) {

      next if ref ${$item_r};
      ${$item_r} = $replace;
      $rep_class3++;

  }
  if (not $rep_class3){
    $class3->splice_content(1, 0, $replace);
  }
  #die qq{Class3 not replaced\n} unless $rep_class3;

  my $edited_html = $root->as_HTML(undef, qq{  }, {});
  return $edited_html;
}

__DATA__
<div align="center" class="class1">something</div>
<div align="center" class="class2">something else</div>
<div align="center" class="class3"></div>

[download]
output 
<html>
  <head>
  </head>
  <body>
    <div align="center" class="class1">something</div>
    <div align="center" class="class2">something else</div>
    <div align="center" class="class3">replaced</div>
  </body>
</html>

[download]

In reply to Re^3: Editing HTML files by wfsp
in thread Editing HTML files by spivey49

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.