What’s the best way to make a d3.js visualisation layout responsive?

Assume I have a histogram script that builds a 960 500 svg graphic. How do I make this responsive so on resize the graphic widths and heights are dynamic?

<script> 

var n = 10000, // number of trials
    m = 10,    // number of random variables
    data = [];

// Generate an Irwin-Hall distribution.
for (var i = 0; i < n; i++) {
  for (var s = 0, j = 0; j < m; j++) {
    s += Math.random();
  }
  data.push(s);
}

var histogram = d3.layout.histogram()
    (data);

var width = 960,
    height = 500;

var x = d3.scale.ordinal()
    .domain(histogram.map(function(d) { return d.x; }))
    .rangeRoundBands([0, width]);

var y = d3.scale.linear()
    .domain([0, d3.max(histogram.map(function(d) { return d.y; }))])
    .range([0, height]);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

svg.selectAll("rect")
    .data(histogram)
  .enter().append("rect")
    .attr("width", x.rangeBand())
    .attr("x", function(d) { return x(d.x); })
    .attr("y", function(d) { return height - y(d.y); })
    .attr("height", function(d) { return y(d.y); });

svg.append("line")
    .attr("x1", 0)
    .attr("x2", width)
    .attr("y1", height)
    .attr("y2", height);

</script> 

Full example histogram gist is:
https://gist.github.com/993912