On click: expanding nodes

[Petkomat]

My graph roughly corresponds to a file system, i.e., the nodes of the graph are directories and files, and the edges correspond to the relation contains, e.g., dir1 -contains-> dir2, dir2 -contains-> file1.

The total number of nodes is too large to show them all at once. This is why I would like to start with some top nodes of the hierarchy and expand a given node on click (to show its neighbours).

Would that be possible with gv.d3(...)?

Is there any other "on click" response that is already implemented?