Round date scale

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.axis text {
  font: 10px sans-serif;
}

.axis path, .axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

</style>
<body>
<script src="https://d3js.org/d3.v2.min.js?2.9.6"></script>
<script>

var margin = {top: 100, right: 100, bottom: 100, left: 100},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var data = [
    {date: new Date(2011,11,31), amount: 200},
    {date: new Date(2012,0,1), amount: 100},
    {date: new Date(2012,0,2), amount: 300},
    {date: new Date(2012,0,3), amount: 400},
    {date: new Date(2012,1,1), amount: 400}
];

var month = data.filter(function (d) { return d.date.getMonth() === 0; });

var x = d3.time.scale()
    .domain(d3.extent(month, function(d) { return d.date; }))
    .range([0, width])
    .nice(d3.time.month);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom")
    .ticks(d3.time.days,7)
    .tickFormat(d3.time.format('%b %d'));

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 + ")");

svg.append("g")
    .attr("class", "x axis")
    .call(xAxis);

</script>

Modified http://d3js.org/d3.v2.min.js?2.9.6 to a secure url

https://d3js.org/d3.v2.min.js?2.9.6