Drawing a Scatterplot

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
		.canvas{width:100%;min-height:600px;}
    .country circle{fill-opacity:.1;stroke:black;stroke-width:1px;}
		.highlight circle{stroke:red;stroke-width:2px;}
		.country text{font-size:10px;}
		.axis .tick line{stroke:rgb(150,150,150);}
		.axis .tick line{stroke-width:.5px;}
  </style>
</head>

<body>
  <div class="container">
    <h1>Drawing a Scatterplot</h1>
    <section class="canvas" id="canvas">
    </section>
	</div>
  <script>
		d3.csv('world_bank_1995_gdp_co2.csv',parse,function(err,rows){
      
      var extentX = d3.extent(rows, function(d){return d.gdpPerCap}),
          extentY = d3.extent(rows, function(d){return d.co2PerCap}),
          extentPop = d3.extent(rows, function(d){return d.pop});
      var scaleX = d3.scalePow().exponent(.5).domain(extentX).range([0,500]),
          scaleY = d3.scalePow().exponent(.5).domain(extentY).range([360,0]),
          scaleSize = d3.scaleSqrt().domain(extentPop).range([2,20]);
      var plot = d3.select('.canvas')
        .append('svg')
        .attr('width',600)
        .attr('height',460)
        .append('g');
      var nodes = plot.selectAll('country')
      	.data(rows)
      	.enter()
      	.append('g')
      	.attr('class','country')
      	.attr('transform',function(d){
        	return 'translate('+scaleX(d.gdpPerCap)+','+scaleY(d.co2PerCap)+')';
        })
      	.on('click',function(d){
        	d3.select(this).classed('highlight',true);
        });
      
      nodes.append('circle').attr('r',function(d){return scaleSize(d.pop);});
      nodes.append('text').text(function(d){return d.code});
      
      var axisX = d3.axisBottom()
        .scale(scaleX)
        .tickSize(-360);
    	var axisY = d3.axisLeft()
        .scale(scaleY)
        .tickSize(-500);
    	plot.append('g').attr('class','axis axis-x')
        .attr('transform','translate(0,'+360+')')
        .call(axisX);
    	plot.append('g').attr('class','axis axis-y').call(axisY);
      
    });
    
    function parse(d){
      if(d['GDP per capita, PPP (constant 2011 international $)']=='..' || d['CO2 emissions (metric tons per capita)']=='..'){
        return;
    }

return {
      name:d['Country Name'],
      code:d['Country Code'],
      gdpPerCap:+d['GDP per capita, PPP (constant 2011 international $)'],
      co2PerCap:+d['CO2 emissions (metric tons per capita)'],
      pop:+d['Population, total']
    }
    }

</script>
</body>

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