我使用的代码与此类似，并且实际上插入了此代码以查看是否得到相同的错误，并且我确实得到了。这是代码:
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
font: 12px Arial;
}
path {
stroke: steelblue;
stroke-width: 2;
fill: none;
}
.axis path,
.axis line {
fill: none;
stroke: grey;
stroke-width: 1;
shape-rendering: crispEdges;
}
.legend {
font-size: 16px;
font-weight: bold;
text-anchor: start;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
var margin = {top: 30, right: 40, bottom: 70, left: 50},
width = 600 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom;
var parseDate = d3.time.format("%d-%b-%y").parse;
var x = d3.time.scale().range([0, width]);
var y0 = d3.scale.linear().range([height, 0]);
var y1 = d3.scale.linear().range([height, 0]);
var xAxis = d3.svg.axis().scale(x)
.orient("bottom").ticks(5);
var yAxisLeft = d3.svg.axis().scale(y0)
.orient("left").ticks(5);
var yAxisRight = d3.svg.axis().scale(y1)
.orient("right").ticks(5);
var valueline = d3.svg.line()
.x(function(d) { return x(d.date); })
.y(function(d) { return y0(d.close); });
var valueline2 = d3.svg.line()
.x(function(d) { return x(d.date); })
.y(function(d) { return y1(d.open); });
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 = [
{"date":"9-Apr-12","close":436,"open":9.04},
{"date":"7-Apr-12","close":221,"open":4.02},
{"date":"5-Apr-12","close":113,"open":9.02},
{"date":"4-Apr-12","close":64,"open":32.05},
{"date":"3-Apr-12","close":29,"open":46.03},
{"date":"2-Apr-12","close":18,"open":51.03}
];
// Get the data
data.forEach(function(d) {
d.date = parseDate(d.date);
d.close = +d.close;
d.open = +d.open;
});
// Scale the range of the data
x.domain(d3.extent(data, function(d) { return d.date; }));
y0.domain([0, d3.max(data, function(d) {
return Math.max(d.close); })]);
y1.domain([0, d3.max(data, function(d) {
return Math.max(d.open); })]);
svg.append("path")
.attr("class", "line")
.attr("id", "blueLine")
.attr("d", valueline(data));
svg.append("path")
.attr("class", "line")
.style("stroke", "red")
.attr("id", "redLine")
.attr("d", valueline2(data));
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
// edit the Y Axis Left
svg.append("g")
.attr("class", "y axis")
.style("fill", "steelblue")
.attr("id", "blueAxis")
.call(yAxisLeft);
svg.append("g")
.attr("class", "y axis")
.attr("transform", "translate(" + width + " ,0)")
.style("fill", "red")
.attr("id", "redAxis")
.call(yAxisRight);
// Add the blue line title
svg.append("text")
.attr("x", 0)
.attr("y", height + margin.top + 10)
.attr("class", "legend")
.style("fill", "steelblue")
.on("click", function(){
// Determine if current line is visible
var active = blueLine.active ? false : true,
newOpacity = active ? 0 : 1;
// Hide or show the elements
d3.select("#blueLine").style("opacity", newOpacity);
d3.select("#blueAxis").style("opacity", newOpacity);
// Update whether or not the elements are active
blueLine.active = active;
})
.text("Blue Line");
// Add the red line title
svg.append("text")
.attr("x", 0)
.attr("y", height + margin.top + 30)
.attr("class", "legend")
.style("fill", "red")
.on("click", function(){
// Determine if current line is visible
var active = redLine.active ? false : true ,
newOpacity = active ? 0 : 1;
// Hide or show the elements
d3.select("#redLine").style("opacity", newOpacity);
d3.select("#redAxis").style("opacity", newOpacity);
// Update whether or not the elements are active
redLine.active = active;
})
.text("Red Line");
</script>
</body>
我得到错误说'蓝线'和'红线'没有定义。
我在哪里定义这些?
我看过类似的代码，其中html, css和js被分隔成自己的文件，这就是我所做的，除了我在上面的代码中看到的，我没有发现这些变量在其他任何地方使用或定义超出了什么。
我用你那里的代码做了一个plunk，一切都很好。让我来解释一下发生了什么。
而不是使用已经存在的HTML, D3将经常生成自己的(事实上，它必须生成自己的可视化)。您可以通过下面的语句看到这一点:svg.append("path")
.attr("class", "line")
.attr("id", "blueLine")
.attr("d", valueline(data));
D3只是创建了一个path元素，并将其附加到之前创建的svg元素。它给这个特定的元素一个blueLine的id，它稍后使用它来应用样式。在此脚本运行之前，它不存在于任何HTML中。