Axis Styling

This example shows how to customize the appearance of d3-axis using post-selection: modifying the contents of the SVG elements created by the axis. This technique can also be applied during transitions.

<!DOCTYPE html>
<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: 0, bottom: 20, left: 0},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var formatNumber = d3.format(".1f");

var x = d3.scaleTime()
    .domain([new Date(2010, 7, 1), new Date(2012, 7, 1)])
    .range([0, width]);

var y = d3.scaleLinear()
    .domain([0, 2e6])
    .range([height, 0]);

var xAxis = d3.axisBottom(x)
    .ticks(d3.timeYear);

var yAxis = d3.axisRight(y)
    .tickSize(width)
    .tickFormat(function(d) {
      var s = formatNumber(d / 1e6);
      return this.parentNode.nextSibling
          ? "\xa0" + s
          : "$" + s + " million";
    });

g.append("g")
    .attr("transform", "translate(0," + height + ")")
    .call(customXAxis);

g.append("g")
    .call(customYAxis);

function customXAxis(g) {
  g.call(xAxis);
  g.select(".domain").remove();
}

function customYAxis(g) {
  g.call(yAxis);
  g.select(".domain").remove();
  g.selectAll(".tick:not(:first-of-type) line").attr("stroke", "#777").attr("stroke-dasharray", "2,2");
  g.selectAll(".tick text").attr("x", 4).attr("dy", -4);
}

</script>

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