2 Level Diverging Bar Chart - 2 DataSets Implimentation

2 Level Diverging Bar Chart, can use 2 different datasets or one (code must be modified). Note how in this version elements are not appended.

<!DOCTYPE html>
<html lang="en">
  <head>
		<meta charset="utf-8">
		<title>2 Level Diverging Bar Chart - 2 DataSets Implimentation</title>
		<script src="https://d3js.org/d3.v3.min.js"></script>
  </head>

var xScale = d3.scale.ordinal()
				.domain(d3.range(dataSet1.length))
				.rangeRoundBands([0, w], 0.05);//calculate even bands + add spacing

var maxDomain = d3.max(dataSet1) / 2 + d3.max(dataSet2) / 2;
			var yScale = d3.scale.linear()
				.domain([0, maxDomain])
				.range([0, h]);

function color(d){ return "rgb(150," + d * 10 + "," + d * 15 + ")"; };

svg.selectAll("rect.valueTop")
				.data(dataSet1)
				.enter()
				.append("rect")
				.attr({
					"class": "valueTop",
					x: function(d, i) { return xScale(i); },
					y: function(d) { return h - yScale(d)/2 - h/2; },
					width: xScale.rangeBand(),
					height: function(d){ return yScale(d) / 2; },
					fill: function(d){ return color(d); }
				});
			svg.selectAll("rect.valueBottom")
				.data(dataSet2)
				.enter()
				.append("rect")
				.attr({
					"class": "valueBottom",
					x: function(d, i) { return xScale(i); },
					y: function(d) { return h/2; },
					width: xScale.rangeBand(),
					height: function(d){ return yScale(d) / 2; },
					fill: function(d){ return "red"; }
				});

svg.selectAll("text.valueTop") // top
				.data(dataSet1)
				.enter()
				.append("text")
				.text(function(d) { return d; })
				.attr({
					"class": "valueTop",
					x: function(d,i) { return xScale(i) + xScale.rangeBand() / 2 },
					y: function(d) { return h - yScale(d)/2 - h/2 + 14; },
				});
			svg.selectAll("text.valueBottom") //bottom
				.data(dataSet2)
				.enter()
				.append("text")
				.text(function(d) { return d; })
				.attr({
					"class": "valueBottom",
					x: function(d,i) { return xScale(i) + xScale.rangeBand() / 2 },
					y: function(d) { return h + yScale(d)/2 - h/2 - 7; },
				});
		</script>
  </body>
</html>

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