Depths question, help needed

Hey guys, check this out.

i’ve attached some buttons from the library, all i need is how do you make them get the next highest depth?

it means when you press a button, it will overlap the other ones (quite a big button)

i’ve tried:

[AS]
btn1.onRollOver = function(){
btn1.getNextHighestDepth()
}
[/AS]

but it doesn’t work,hahah, din’t think it would be that easy.

help needed!