D3: Multi-Line Chart

<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="utf-8">
		<title>US Passports 1996-2014</title>
		<script type="text/javascript" src="https://d3js.org/d3.v3.js"></script>
		<style type="text/css">
			
		body {
			background:#24263F;
			font-family: 'Open Sans',Helvetica,arial,sans-serif;
		}
		h1 {
			font-weight: 600;
			text-transform: uppercase;
		}
		header {
			color: #F4D73C;
		}
		hr {
			border: 2px solid #F4D73C;
			margin-top: 20px;
			margin-left: 10px;
			margin-right: 10px;
		}
		a {
			color: #F4D73C;
			text-decoration: underline;
		}
		svg {
			background: #24263F;
			float:left;
		}
		.axis path,
		.axis line {
			fill: none;
			stroke: #F4D73C;
			shape-rendering: crispEdges;
		}
		.axis text {
			font-family: sans-serif;
			font-size: 11px;
			fill: #F4D73C;
		}
		img {
			float:left;
			height: 100px;
			width: 100px;
			margin-right: 10px;
			margin-left: 10px;
		}
		.explanatory {
			color: #F4D73C;
			font-size: 14px;
			padding: 10px 25px 0 0;
			margin: 25px 25px 225px 88px;
		}
		.legend {
			text-transform: uppercase;
		}
		</style>
	</head>
	<body>
		<header>
			<img src="https://joshuafrazier.info/images/seal.png">
		<h1>United States Passports</h1>
		<p>Applications and Issuances: 1996-2014 (Fiscal Years).<br /> Source: <a href="https://travel.state.gov/content/passports/english/passports/statistics.html">Bureau of Consular Affairs</a></p>
		</header>
		<hr>

//Dimensions and padding
			var w = 1000;
			var h = 500;
			var padding = [ 20, 10, 50, 100 ];  //Top, right, bottom, left

//Set up date formatting and years
			var dateFormat = d3.time.format("%Y");

//Set up scales
			var xScale = d3.time.scale()
								.range([ padding[3], w - padding[1] - padding[3] ]);
			
			var yScale = d3.scale.linear()
								.range([ padding[0], h - padding[2] ]);

//Configure axis generators
			var xAxis = d3.svg.axis()
							.scale(xScale)
							.orient("bottom")
							.ticks(20)
							.tickFormat(function(d) {
								return dateFormat(d);
							});

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

//Configure line generator
			var line = d3.svg.line()
				.x(function(d) {
					return xScale(dateFormat.parse(d.year));
				})
				.y(function(d) {
					return yScale(d.numbers);
				});

//Create the empty SVG image
			var svg = d3.select("body")
						.append("svg")
						.attr("width", w)
						.attr("height", h);

//Load passport issued data
			d3.csv("passports_issued.csv", function(issuedData) {

//Load passport application data
				d3.csv("passport_applications.csv", function(appliedData) {

//Create a new array that contains both the
					//applied for and issued data, merged into one
					var mergedData = issuedData.concat(appliedData);
					//console.log(mergedData);

//Use the newly merged data to determine the
					//min and max values, for setting scale domains
					xScale.domain([ 
						d3.min(mergedData, function(d) {
							return dateFormat.parse(d.year);
						}),
						d3.max(mergedData, function(d) {
							return dateFormat.parse(d.year);
						})
					]);

yScale.domain([ 
						d3.max(mergedData, function(d) {
							return +d.numbers;
						}),
						0
					]);

//Lines
					//
					// Note data is wrapped in another array, so all its
					// values are bound to a single element (the line!)
					//
					svg.data([ issuedData ])
						.append("path")
						.attr("class", "line issued")
						.attr("d", line)
						.attr("fill", "none")
						.attr("stroke", "#ff6666")
						.attr("stroke-width", 2);

svg.data([ appliedData ])
						.append("path")
						.attr("class", "line applied")
						.attr("d", line)
						.attr("fill", "none")
						.attr("stroke", "#FFFFFF")
						.attr("stroke-width", 2);

//Axes
					svg.append("g")
						.attr("class", "x axis")
						.attr("transform", "translate(0," + (h - padding[2] + 10) + ")")
						.call(xAxis);

svg.append("g")
						.attr("class", "y axis")
						.attr("transform", "translate(" + (padding[3] - 10) + ",0)")
						.call(yAxis);

});
				//End passports applied for data load function

});
			//End passports issued data load function
			
					//legend
					svg.append("text")
            		.attr("x",w-225)
            		.attr("y", h-125)
            		.attr("class", "legend")
            		.style("fill", "#FFFFFF")
            		.text("Applications");
					
					svg.append("text")
            		.attr("x",w-225)
            		.attr("y", h-100)
            		.attr("class", "legend")
            		.style("fill", "#ff6666")
            		.text("Issuances");
			
					//explanatory
					var para = d3.select("body")
					.append("p")
					.attr("class", "explanatory")
					.html("1997-2007: the number of passports applied for and issued more than tripled.<br/><br/>2001: after the World Trade Center attacks the gap between applications and issuances gets larger, possibly indicating stricter legal requirements or more stringent adjudication. <br/><br/>2007: the <a href='https://en.wikipedia.org/wiki/Western_Hemisphere_Travel_Initiative'> Western Hemisphere Travel Initiative</a> was implemented requiring travelers to show a valid passport or other approved document when traveling to the US from areas within the Western Hemisphere.<br/><br/>2008: passport cards were introduced.  One application can be used for a passport book and a passport card thus allowing for the total number of issuances (books and cards) to exceed the number of applications.");

</script>

</body>
</html>

Modified http://d3js.org/d3.v3.js to a secure url

https://d3js.org/d3.v3.js