I am trying to display the leaf name when it is clicked, but I am unsure how to do it. I am new to D3 and would appreciate any guidance on how to achieve this. Source: http://bl.ocks.org/mbostock/7607535
var circle = svg.selectAll("circle")
.data(nodes)
.enter().append("circle")
.attr("class", function(d) { return d.parent ? d.children ? "node" : "node node--leaf" : "node node--root"; })
.style("fill", function(d) { return d.children ? color(d.depth) : null; })
.on("click", function(d) { if (focus !== d) zoom(d), d3.event.stopPropagation(); else alert(d3.select(this).name); });