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<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width" />
<title>D3 Line Chart</title>
<link rel="stylesheet" href="style.css">
<script src="//d3js.org/d3.v3.min.js" charset="utf-8"></script>
</head>
<body>
<div id="chart"></div>
<script src="chart.js"></script>
</body>
</html>
https://d3js.org/d3.v3.min.js