Dynamic rearrange of tree-elements?

[guevaradelaserna]

I visualized a tree structure with svg. It allows nodes to dynamically show and hide.However, the sub-nodes have been always the same distance. Now I want that this distance is determined according to the number of neighboring nodes. Thesubnodes are each grouped and arranged by translate to the previous nodes.

Do you know a JavaScript library which can solve this problem, or you may havean approach?

Thanks Alex