Horizontal Bar Chart with Tooltip D3 V4

This chart shows average house prices in various areas of Liverpool, UK

d3.json - load and parse data
d3.tickFormat - format y axis tick text
d3.scale.ordinal - x-position encoding
d3.scale.linear - y-position encoding
d3.max - compute domains
d3.svg.axis - display axes

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
  margin: 15px;
  background-color: #F1F3F3    
}
.bar {
	fill: #6F257F;
}
.axis path,
.axis line {
  fill: none;
  stroke: #D4D8DA;
  stroke-width: 1px;
  shape-rendering: crispEdges;
}
.x path {
	display: none;
}
.toolTip {
	position: absolute;
  display: none;
  min-width: 80px;
  height: auto;
  background: none repeat scroll 0 0 #ffffff;
  border: 1px solid #6F257F;
  padding: 14px;
  text-align: center;
}
</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 30, left: 80},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom;
  
var tooltip = d3.select("body").append("div").attr("class", "toolTip");
  
var x = d3.scaleLinear().range([0, width]);
var y = d3.scaleBand().range([height, 0]);

g.append("g")
        .attr("class", "x axis")
       	.attr("transform", "translate(0," + height + ")")
      	.call(d3.axisBottom(x).ticks(5).tickFormat(function(d) { return parseInt(d / 1000); }).tickSizeInner([-height]));

g.append("g")
        .attr("class", "y axis")
        .call(d3.axisLeft(y));

g.selectAll(".bar")
        .data(data)
      .enter().append("rect")
        .attr("class", "bar")
        .attr("x", 0)
        .attr("height", y.bandwidth())
        .attr("y", function(d) { return y(d.area); })
        .attr("width", function(d) { return x(d.value); })
        .on("mousemove", function(d){
            tooltip
              .style("left", d3.event.pageX - 50 + "px")
              .style("top", d3.event.pageY - 70 + "px")
              .style("display", "inline-block")
              .html((d.area) + "<br>" + "£" + (d.value));
        })
    		.on("mouseout", function(d){ tooltip.style("display", "none");});
});
</script>

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