Javascript Binary Tree

I want to create a javscript recursive program using a Binary Tree and Recursion.

var user = [
{ id: 1, ref: 0 },
{ id: 2, ref: 1 },
{ id: 3, ref: 2 },
{ id: 4, ref: 3 },
{ id: 5, ref: 4 },
{ id: 6, ref: 5 },
{ id: 7, ref: 1 }
];

OUTPUT

{ id: 2, level: 1},
{ id: 3, level: 2},
{ id: 4, level: 3},
{ id: 5, level: 4},
{ id: 6, level: 5},
{ id: 7, level: 1}

via Jiw Kittipong