I want to insert a large chunk of html into a pre-existing
You should probably be creating your elements with jquery, rather than in a big string. You get no certainty of dom correctness if you just use a big string, and it's near impossible to debug or modify. This is similar to building xml by hand. It's just not the preferred way of doing it.. I am using this method:
$(\"td#content\").html(LOTS_OF_HTML_CODE_HERE);