Method For Storing an N-Depth Tree

I need to store a tree in a javascript object or array. There is one root element with N children. Each child can have N children, and so on. The last branch node holds a number.

Real world example:

Hats
    Child
        Blue -> 12
        Green -> 23
        Purple -> 31
        Red -> 14
    Adult
        Black -> 15
        White -> 56
        Gray -> 173

Code (markup):

I think an associative array would be the best option, but I've read that they aren't supported. What is next best method for storing this type of data?

 

Looks like xml to me...

 

{
	Hats : {
		child : {
			Blue : 12,
			Green : 23,
			Purple : 31,
			Red : 14
		},
		Adult : {
			Blac...etc,
			etc,
		}
	}
}

Code (markup):

JSON; the next best thing since sliced bread.