javascript dhtml framework?

hello

I am looking for a javascript / dhtml / ajax framework.

something that will allow me to:

1. create menus dynamically, such as:

var x = new Menu();
x.newMenuItem(new MenuItem('yadsad'));

etc...to build a complete menu structure ,as if programming the windows
api.

2. create windows
resizable, maximizable, closable dhtml windows

3. create a status bar object..

allows one to create a status bar, whose elements/columns are easily
accessible.

4. allows loading of external html files into a given dhtml window

5. ajax libraries in that framework

etc....

anyone knows such a javascript framework?