scatterplot in progress

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    
    circle {
      fill: black;
    }
  </style>
</head>

<body>
  <script>
  var margin = {top: 20, right: 10, bottom: 20, left: 30};

var width = 960 - margin.left - margin.right,
      height = 500 - margin.top - margin.bottom;

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 color = d3.scaleOrdinal(d3.schemeCategory20);
        
  var x = d3.scaleLinear()
      .range([0, width]);

var y = d3.scaleLinear()
      .range([height, 0]);
 
	var r = d3.scaleSqrt()
      .range([2, 10]);

var xAxis = d3.axisBottom()
		.scale(x);

var yAxis = d3.axisLeft()
      .scale(y);
  
  xAxis(svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")"))

svg.append('g')
    .attr('transform', 'translate(0,0)')
    .attr('class', 'y axis')
    .call(yAxis);

d3.csv('iris.csv', function(error, data){
    
    data.forEach(function(d){
      d.sepal_length = +d.sepal_length;
      d.sepal_width  = +d.sepal_width;
      d.petal_length = +d.petal_length;
      d.petal_width  = +d.petal_width;
    });
    
		x.domain(d3.extent(data, function(d) { return d.sepal_length; }));
		y.domain(d3.extent(data, function(d) { return d.sepal_width; }));
		r.domain(d3.extent(data, function(d) { return d.petal_length; }));

svg.selectAll(".dot").data(data).enter()
  	.append("circle")
  	.attr("class", "dot")
  	.attr("cx", function(d) { return x(d.sepal_length); })
  	.attr("cy", function(d) { return y(d.sepal_width); })
  	.attr("r", function(d) { return r(d.sepal_width); })
  	.style("fill", function(d) { return color(d.species); });
 
  });
    
  </script>
</body>

https://d3js.org/d3.v4.min.js