D3 line chart: Album sales down

<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="utf-8">
		<title>Line Chart with Multiple Lines</title>
		<script type="text/javascript" src="https://d3js.org/d3.v3.js"></script>
		<link rel="stylesheet" type="text/css" href="styles.css">
	</head>
	<body>
		<h1>Album sales down since 2008</h1>

<p>Shown is album sales in the United States by genre. Data provided by <a href="https://www.statista.com/statistics/188910/us-music-album-sales-by-genre-2010/" target="_blank">Statista</a>.</p>

//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("top")
				.tickFormat(function(d) {
					return dateFormat(d);
				});

var yAxis = d3.svg.axis()
				.scale(yScale)
				.orient("left")
				.tickFormat(function(d) {
					if (d === 0) {
						return 0;
					} else {
						return '$' + d + 'M';
					}
				});

//Configure line generator
			var line = d3.svg.line()
				.x(function(d) {
					return xScale( dateFormat.parse( d['time_interval'] ) );
				})
				.y(function(d) {
					return yScale( +d['amount'] );
				});

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

//Load data
			d3.csv("record_sales.csv", function(data) {
				// Restructed data should look like so:
				/*

[
						{
							country: "Australia",
							emissions: [
										{ year: 1961, amount: 90589.568 },
										{ year: 1962, amount: 94912.961 },
										{ year: 1963, amount: 101029.517 },
										…
									   ]
						},
						{
							country: "Bermuda",
							emissions: [
										{ year: 1961, amount: 176.016 },
										{ year: 1962, amount: 157.681 },
										{ year: 1963, amount: 150.347 },
										…
									   ]
						},
						…
					 ]

//New array with all the years, for referencing later
				var time_inverals = ["2008", "2009", "2010","2011","2012","2013","2014"];

//Create a new, empty array to hold our restructured dataset
				var dataset = [];

//Loop once for each row in data
				for (var num = 0; num < data.length; num++) {
					//Create new object with this country's name and empty array
					dataset[num] = {
						'name': data[num]['Genre'],
						'time_data': []
					};

//Loop through all the years
					for (var num_two = 0; num_two < time_inverals.length; num_two++) {
						// If value is not empty
						if ( data[num][time_inverals[num_two]] ) {

//Add a new object to the data array
							//for this entry
							dataset[num]['time_data'].push({
								'time_interval': time_inverals[num_two],
								'amount': data[num][time_inverals[num_two]]
							});
						}
					}
				// Close for loop
				}
				
				//Uncomment to log the original data to the console
				// console.log(data);

//Uncomment to log the newly restructured dataset to the console
				// console.log(dataset);

//Set scale domains
				xScale.domain([ 
					d3.min(time_inverals, function(d) {
						return dateFormat.parse(d);
					}),
					d3.max(time_inverals, function(d) {
						return dateFormat.parse(d);
					})
				]);

yScale.domain([ 
					d3.max(dataset, function(d) {
						return d3.max(d['time_data'], function(d) {
							return +d['amount'];
						});
					}),
					0
				]);

//Make a group for each country
				var groups = svg.selectAll("g")
					.data(dataset)
					.enter()
					.append("g")

//Append a title with the name (so we get easy tooltips)
				groups.append("title")
					.text(function(d) {
						return d['name'];
					});

// Within each group, create a new line/path,
				// binding just the right data to each one
				var paths = groups.selectAll("path")
					.data(function(d) {
						return [ d['time_data'] ];
					})
					.enter()
					.append("path")
					.attr("class", "line")
					.attr("d", line)
					.attr("fill", "none")
					.attr('stroke','steelblue')
					.attr("stroke-width", 2)
					.attr("opacity",0);

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

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

// Fade in
				paths.transition()
					.duration(2000)
					.attr("opacity",1)

});
			//End USA data load function
		</script>
	</body>
</html>

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

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