source: Dev/trunk/d3/examples/box/box.js @ 76

var w = 120,
    h = 500,
    m = [10, 50, 20, 50], // top right bottom left
    min = Infinity,
    max = -Infinity;

var chart = d3.chart.box()
    .whiskers(iqr(1.5))
    .width(w - m[1] - m[3])
    .height(h - m[0] - m[2]);

d3.csv("../data/morley.csv", function(csv) {
  var data = [];

  csv.forEach(function(x) {
    var e = ~~x.Expt - 1,
        r = ~~x.Run - 1,
        s = ~~x.Speed,
        d = data[e];
    if (!d) d = data[e] = [s];
    else d.push(s);
    if (s > max) max = s;
    if (s < min) min = s;
  });

  chart.domain([min, max]);

  var vis = d3.select("#chart").selectAll("svg")
      .data(data)
    .enter().append("svg:svg")
      .attr("class", "box")
      .attr("width", w)
      .attr("height", h)
    .append("svg:g")
      .attr("transform", "translate(" + m[3] + "," + m[0] + ")")
      .call(chart);

  chart.duration(1000);
  window.transition = function() {
    vis.map(randomize).call(chart);
  };
});

function randomize(d) {
  if (!d.randomizer) d.randomizer = randomizer(d);
  return d.map(d.randomizer);
}

function randomizer(d) {
  var k = d3.max(d) * .02;
  return function(d) {
    return Math.max(min, Math.min(max, d + k * (Math.random() - .5)));
  };
}

// Returns a function to compute the interquartile range.
function iqr(k) {
  return function(d, i) {
    var q1 = d.quartiles[0],
        q3 = d.quartiles[2],
        iqr = (q3 - q1) * k,
        i = -1,
        j = d.length;
    while (d[++i] < q1 - iqr);
    while (d[--j] > q3 + iqr);
    return [i, j];
  };
}