I have a div that is contain inside an iframe from a external html
The html based \"context menu\" need to
Your really duplicating typical "Ajax" functionality, since its already been abstracted by many frameworks (like jQuery), and you are not likely to do it any better I'd give that a shot. Don't reinvent the wheel.
You can find a great example here.
$("#links").load("/Main_Page #jq-p-Getting-Started li");