my $str = q{
<span id=editArea name="whatever">
bla bla a bunch of html and text that will change from file to file
</span>
};

use HTML::TreeBuilder;

my $t = HTML::TreeBuilder->new_from_content($str);

foreach ($t->look_down('_tag', 'span')) {
	next if $_->attr('id') ne 'editArea' || $_->attr('name') ne 'whatever';
	$_->delete_content;
	$_->push_content('this is some replacement text');	
}

print $t->as_HTML;
$t->delete;