get_children
is the most straightforward way to get “attachments, revisions, or sub-Pages”. So…
$children = get_children(array('post_parent'=>$post->ID));
if (!empty($children)) {
foreach ($children as $child) {
echo '<div id="child-'.$child->ID.'" >';
// content formatted however you want
echo '</div>';
}
See the Codex page for further parameters that you might need.
I don’t know how you’ve constructed your drop-down menu but you can link to any element on the page using its id
attribute so your href
for the links should be #child-<ID>
, preferably constructed as an absolute URL.