This is a simple d3.js tree diagram, arranged so that the tree is vertical, as used as an example in the book D3 Tips and Tricks.
It is derived from the Mike Bostock Collapsible tree example but it is a VERY cut down version without the ability to update (collapse).
There is an error in the constructor of the tree layout
var tree = d3.layout.tree().size([height, width]);
The width and height properties are in the wrong order. Should bevar tree = d3.layout.tree().size([width, height]);