[Flash 8] Need help in understanding this code!

programming flash
1

Hi all,

I just started learning Flash Actionscript.

Can anyone explain to me what this sentence means?

this._y = random(Stage.height)-(this._height/2)-Stage.height-200;

I got it from a code that make ball falling from top to bottom and i analysis that is this code that make it work. I wanted to change the code to make float from bottom to top.

Can anyone help?

Thank in advance

Regards,
Wai