Simple D3 Pie Chart

aAn example of a simple pie chart drawn with D3.js

HTML

<div id="chart"></div>

JavaScript

var w = 400;
var h = 400;
var r = h / 2;
var color = d3.scale.category20c();

var data = [{
  "label": "Category B",
  "value": 70
}, {
  "label": "Category A",
  "value": 30
}];


var vis = d3.select('#chart').append("svg:svg").data([data]).attr("width", w).attr("height", h).append("svg:g").attr("transform", "translate(" + r + "," + r + ")");
var pie = d3.layout.pie().value(function(d) {
  return d.value;
});

// declare an arc generator function
var arc = d3.svg.arc().outerRadius(r);

// select paths, use arc generator to draw
var arcs = vis.selectAll("g.slice").data(pie).enter().append("svg:g").attr("class", "slice");
arcs.append("svg:path")
  .attr("fill", function(d, i) {
    return color(i);
  })
  .attr("d", function(d) {
    // log the result of the arc generator to show how cool it is :)
    console.log(arc(d));
    return arc(d);
  });