I've a medium experience with actionscript 3 and i know his logic.
For create an element1, nest into it an element2 and show it on the stage i've simple to write

var element1: MovieClip = new MovieClip()
var element2: MovieClip = new MovieClip()

element1.addChild(element2)
addChild(element1) //add element1, comprensive of element2 on the scene


I would want to understand the logic behind JS consider the example reported above..

I'm reading the Javascript Complete Guide, and according to what i understand i've to create manually an object (element1) and include inside another object (element2)...
The code will be something of genre:

var element1 = {var element2:somevalue}

1) What if i want to add an element in runtime phase?
In AS3 i would use the method addChild included in the MovieClip class, but JS seems not have anything of genre

2) How add element1 on the "stage", in other words, make it visible to the user and not an abstract entity?