index.html

## index.html
<!doctype html>
<meta charset="UTF-8">
<style type="text/css" media="screen">
  .path {
    stroke: #c00;
    stroke-width: 1;
    fill: none;
  }
</style>
<script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
<body>

  <script type="text/javascript" charset="utf-8">
    var data = [5, 3, 5, 4, 4, 5, 6, 7, 2, 5]

    var width = 500,
        height = 500

    var vis = d3.select('body').append('svg')
      .attr('width', 500)
      .attr('height', 500)

    var extent = d3.extent(data)
    var x = d3.scale.linear().domain([0, data.length]).range([0, width]),
        y = d3.scale.linear().domain(extent).range([0, height])

    var path = d3.svg.line()
      .x(function(d, i) { return x(i) })
      .y(y)

    vis.append('path')
      .datum(data)
      .attr('class', 'path')
      .attr('d', path)
  </script>
</body>