How can I remove an entire HTML tag (and its contents) by its class using a regex?

<div class="footer".*?>(.*?)</div>

<div[^>]*class="footer"[^>]*>(.*?)</div>

<div>
    <div class="footer">
        <div>Hi!</div>
    </div>
</div>

document = //load document
divs = document.getElementsByTagName("div");
for(div in divs) {
    if(div.getAttributes["class"] == "footer") {
        parent = div.getParent();
        for(child in div.getChildren()) {
            // filter attribute types?
            parent.insertBefore(div, child);
        }
        parent.removeChild(div);
    }
}

use HTML::TreeBuilder::XPath;

my $tree = HTML::TreeBuilder::XPath->new;
$tree->parse_file( 'yourdocument.html' );

for my $node ( $tree->findnodes( '//*[@class="footer"]' ) ) {
    $node->replace_with_content;   # delete element, but not the children
}

print $tree->as_HTML;

<div class="footer".*?>(.*?)</div>

<([^s]+).*?class="footer".*?>([.n]*?)</([^s]+)>

<div class="footer"><b></b></div>

<div[^>]*class="footer"[^>]*>(.*?)</div>

<div[^>]*class="footer"[^>]*>(.*?)</div>