adding controls to div programmatically

[de]

I'm trying to create a composite control w/o knowing much about it. I
should probably get a book and start at chapter 1 but in the hopes of
saving time, I'm posting. Do the control books ever use javascript,
anyway?

I'm inheriting from webcontrol and have added a textbox, a listbox, a
requiredFieldValidator, and a HtmlGenericControl (div). I want to show
and hide the listbox via javascript. I've add appropriate attributes to
my controls so that the javascripts should be called. I want to put
the listbox (lb) in the div (div)programmatically but don't know how. I
tried div.Controls.Add(lb). Any help?