无法使用d3显示折线图

var margin = {
    top: 30,
    right: 20,
    bottom: 30,
    left: 50
};
var width = 600 - margin.left - margin.right;
var height = 270 - margin.top - margin.bottom;

var x = d3.scale.linear().range([0, width]);
var y = d3.scale.linear().range([height, 0]);

var xAxis = d3.svg.axis().scale(x)
    .orient("bottom").ticks(5);

var yAxis = d3.svg.axis().scale(y)
    .orient("left").ticks(5);

var valueline = d3.svg.line()
    .x(function (d) {
      return x(d.IP);
    })
    .y(function (d) {
      return y(d.count);
    });

var svg = d3.select("body")
    .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var data = [{
    "IP": "192.168.12.1",
    "count": "100"
}, {
    "IP": "76.09.45.34",
    "count": "200"
}, {
    "IP": "34.91.23.76",
    "count": "300"
}, {
    "IP": "192.168.19.32",
    "count": "400"
}, {
    "IP": "192.168.10.89",
    "count": "500"
}, {
    "IP": "192.168.12.98",
    "count": "600"
}];

data.forEach(function (d) {
    d.IP = d.IP;
    d.count = +d.count;
});

x.domain(d3.extent(data, function (d) {
    return d.IP;
    }));
y.domain([0, d3.max(data, function (d) {
    return d.count;
    })]);

svg.append("path")
.attr("d", valueline(data));

svg.append("g")
	.attr("class", "x axis")
	.data(data)
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis);

svg.append("g")
	.attr("class", "y axis")
    .call(yAxis)
    .data(data);var margin = {
    top: 30,
    rig