基于d3.js实现实时刷新的折线图

function loadLineChart(elementId, dataset) {
 var svg = d3.select("#" + elementId);
 var strs = svg.attr("viewBox").split(" ");
 alert(dataset);
 var width = strs[2];
 var height = strs[3];

 //外边框
 var padding = {
 top : 50,
 right : 50,
 bottom : 50,
 left : 50
 };

 var names = new Array();
 //计算GDP的最大值
 var gdpmax = 0;
 for (var i = 0; i  gdpmax)
  gdpmax = currGdp;

 }
 var gdpnumb = dataset[0].gdp.length;
 for (var j = 0; j 中所有的
 .data(dataset) //绑定数据
 .enter() //选择enter部分
 .append("path") //添加足够数量的元素
 .attr("transform", "translate(" + padding.left + "," + padding.top + ")")
 .attr("d", function (d) {
 return linePath(d.gdp); //返回直线生成器得到的路径
 })
 .attr("fill", "none")
 .attr("stroke-width", 3)
 .attr("stroke", function (d, i) {
 return colors[i];
 });

 //添加垂直于x轴的对齐线
 var vLine = svg.append("line")
 .attr("class", "focusLine")
 .style("display", "none");

 //添加一个提示框
 var tooltip = d3.select("body")
 .append("div")
 .attr("class", "tooltip")
 .style("opacity", 0.0);

 var title = tooltip.append("div")
 .attr("class", "title");

 var des = tooltip.selectAll(".des")
 .data(dataset)
 .enter()
 .append("div");

 var desColor = des.append("div")
 .attr("class", "desColor");

 var desText = des.append("div")
 .attr("class", "desText");

 //添加一个透明的监视鼠标事件用的矩形
 svg.append("rect")
 .attr("class", "overlay")
 .attr("x", padding.left)
 .attr("y", padding.top)
 .attr("width", width - padding.left - padding.right)
 .attr("height", height - padding.top - padding.bottom)
 .on("mouseover", function () {
 tooltip.style("left", (d3.event.pageX) + "px")
 .style("top", (d3.event.pageY + 20) + "px")
 .style("opacity", 1.0);

 vLine.style("display", null);
 })
 .on("mouseout", function () {
 tooltip.style("opacity", 0.0);
 vLine.style("display", "none");
 })
 .on("mousemove", mousemove);

 function mousemove() {
 /* 当鼠标在透明矩形内滑动时调用 */

 //折线的源数组
 var data = dataset[0].gdp;

 //获取鼠标相对于透明矩形左上角的坐标，左上角坐标为(0,0)
 var mouseX = d3.mouse(this)[0] - padding.left;
 var mouseY = d3.mouse(this)[1] - padding.top;

 //通过比例尺的反函数计算原数据中的值，例如x0为某个年份，y0为GDP值
 var x0 = xScale.invert(mouseX);
 var y0 = yScale.invert(mouseY);

 //对x0四舍五入，如果x0是2005.6，则返回2006；如果是2005.2，则返回2005
 x0 = Math.round(x0);

 //查找在原数组中x0的值，并返回索引号
 var bisect = d3.bisector(function (d) {
  return d[0];
  }).left;
 var index = bisect(data, x0);

 //获取年份和gdp数据
 var year = x0;
 var gdp = [];

 for (var k = 0; k " + year + "年");

 //设置颜色标记的颜色
 desColor.style("background-color", function (d, i) {
  return colors[i];
 });

 //设置描述文字的内容
 desText.html(function (d, i) {
  return gdp[i].country + "\t" + "" + gdp[i].value + "";
 });

 //设置提示框的位置
 tooltip.style("left", (d3.event.pageX) + "px")
 .style("top", (d3.event.pageY + 20) + "px");

 //获取垂直对齐线的x坐标
 var vlx = xScale(data[index][0]) + padding.left;

 //设定垂直对齐线的起点和终点
 vLine.attr("x1", vlx)
 .attr("y1", padding.top)
 .attr("x2", vlx)
 .attr("y2", height - padding.bottom);
 }

 var markStep = 80;

 var gMark = svg.selectAll(".gMark")
 .data(dataset)
 .enter()
 .append("g")
 .attr("transform", function (d, i) {
  return "translate(" + (padding.left + i * markStep) + "," + (height - padding.bottom + 40) + ")";
 });

 gMark.append("rect")
 .attr("x", 0)
 .attr("y", 0)
 .attr("width", 10)
 .attr("height", 10)
 .attr("fill", function (d, i) {
 return colors[i];
 });

 gMark.append("text")
 .attr("dx", 15)
 .attr("dy", ".5em")
 .attr("fill", "black")
 .text(function (d) {
 return d.country;
 });

 //x轴
 var xAxis = d3.svg.axis()
 .scale(xScale)
 .ticks(5)
 .tickFormat(d3.format("d"))
 .orient("bottom");

 //y轴
 var yAxis = d3.svg.axis()
 .scale(yScale)
 .orient("left");

 svg.append("g")
 .attr("class", "axis")
 .attr("transform", "translate(" + padding.left + "," + (height - padding.bottom) + ")")
 .call(xAxis);

 svg.append("g")
 .attr("class", "y axis")
 .attr("transform", "translate(" + padding.left + "," + padding.top + ")")
 .call(yAxis);

 function updateLineChart() {

 this.update = function (updateData) {
  //xScale.domain(updateData,function(d){return d.name});
  var numValues = updateData.length;
  var updategdpmax = 0;
  for (var i = 0; i  updategdpmax)
   updategdpmax = currGdp;
  }

  yScale = d3.scale.linear()
  .domain([0, updategdpmax * 1.1])
  .range([height - padding.top - padding.bottom, 0]);
  yAxis = d3.svg.axis()
  .scale(yScale)
  .orient("left");
  svg.selectAll("g.y.axis")
  .call(yAxis);

  svg.selectAll("path") //选择

svg.selectAll("g.y.axis")
  .call(yAxis);