How to make this Bar chart responsive

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<dynamic>" %>

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
    Index
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <h2>Bar Chart | Salary</h2>

<script src="http://d3js.org/d3.v3.min.js" type="text/javascript"></script>
<style>
</style>
    <div id="test-chart"></div>
    <script>
        var json =  [
                { "EmpID": 1, "Salary": 21 },
                { "EmpID": 2, "Salary": 12 },
                { "EmpID": 3, "Salary": 11 },
                { "EmpID": 4, "Salary": 15 },
                { "EmpID": 5, "Salary": 14 },
                { "EmpID": 6, "Salary": 19 },
                { "EmpID": 7, "Salary": 16}]
        var w = 645;
        var h = 300;
        var x = d3.scale.linear()
    .domain([0, d3.max(json, function (d) { return d.Salary; })])
    .range([0, w]);
        var y = d3.scale.ordinal()
    .domain(d3.range(json.length))
    .rangeBands([0, h], 0.1);

        // Definig color Property
        var color = d3.scale.ordinal()
                .range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#a05d56", "#d0743c", "#ff8c00"]);

        // Adding SVG canvas
        var svg = d3.select("#test-chart")
    .append("svg")
    .attr("width", w)
    .attr("height", h)
    .append("g")
    .attr("transform", "translate(20,0)");

    // for Values rep
        var bars = svg.selectAll(".bar")
    .data(json)
    .enter().append("g")
    .attr("class", "bar")
    .attr("transform", function (d, i) { return "translate(" + 0 + "," + y(i) + ")"; });

     bars.append("rect")
    .attr("fill", function (d, i) { return color(i); })
    .attr("width", function (d) { return x(d.Salary); })
    .attr("height", y.rangeBand());

       bars.append("text")
      .attr("x", function (d) { return x(d.Salary); })
      .attr("y", 0 + y.rangeBand() / 2)
      .attr("dx", -18)
      .attr("dy", ".35em")
      .attr("text-anchor", "end")
      .text(function (d) { return d.Salary; });

    </script>

</asp:Content>