IMHO, I'm not a big fan of having my perl code mixed with HTML code. When I really began seperating my logic (perl code) from my presentation code (HTML and the template language), my web-based apps became infinitely simpler to maintain, and develop.

To get this seperation I use HTML::Template. With this module, you can alternate the colors for each row of data, all from within the template.

Here's a simple example that will alternate between two colors inside a template:

  <!-- TMPL_LOOP NAME="rows" -->
    <!-- TMPL_IF NAME="__ODD__" -->
      #FFFFFF
    <!-- TMPL_ELSE -->
      #DDDDFF
    <!-- /TMPL_IF -->
  <!-- /TMPL_LOOP -->
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(Of course, in the a real-world this would contain more HTML code, but I didn't want to clutter the example)

Then I'd use the following code to load the template, loop through the rows, print the results, and alternate the colors on each iteration:

my $template = HTML::Template->new(
  filename          => 'template_name.tmpl',
  loop_context_vars => 1,
);

$template->param(rows => $dbh->selectall_hashref($statement));

print $cgi->header, $template->output;
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Now, you could do this inside perl code, but I really believe that when you begin to include things other than perl code inside your perl scripts, they become less maintainable, and less elegant.