I want to insert a large chunk of html into a pre-existing
If it's coming in from a link, you'll probably want to do it with AJAX: However, keep in mind if you're trying to pull HTML from a site on a different domain you'll need to use server proxies and all that stuff...kind of out of the scope of the question.. I am using this method:
$(\"td#content\").html(LOTS_OF_HTML_CODE_HERE);
$("#YOUR_ELEMENT").load("THE_CONTENT_TO_LOAD");