Ordinal Scale - Days of Week

HTML

<script src="https://rawgit.com/eu81273/jsfiddle-console/master/console.js"></script>

CSS

html
{
    background:#f9f9f9;
}
body {
  font: 10px sans-serif;
}

path
{
    stroke: #e0553d;
    stroke-width: 2;
    fill: none
}

.axis path, .axis line
{
    fill: none;
    stroke: grey;
    stroke-width: 1;
    shape-rendering: crispEdges;
}

svg
{
    display:block;
    border:1px solid #ebebeb;
    background:#fff;
}

JavaScript

var data=[{"Day":"Sunday","EC":1},{"Day":"Monday","EC":4424},{"Day":"Tuesday","EC":3408},{"Day":"Wednesday","EC":3137},{"Day":"Thursday","EC":2239},{"Day":"Friday","EC":3090},{"Day":"Saturday","EC":209}];

var days=['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday']

// set up a drawing context
var margin = {
    top: 40,
    right: 40,
    bottom: 70,
    left: 100
};
var width = 540 - margin.left - margin.right;
var height = 330 - margin.top - margin.bottom;
// d3 init
x = d3.scale.ordinal().domain(days).rangePoints([0, width]);
var y = d3.scale.linear().range([height, 0]);

var xAxis = d3.svg.axis().scale(x).orient("bottom")
        .ticks(6)
var yAxis = d3.svg.axis().scale(y).orient("left").ticks(10);
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 + ")"
);
var valueline = d3.svg.line()
        .x(function(d) {
            return x(d.Day); })
        .y(function(d) {
            return y(d.EC);});


    // Scale the range of the data
    //x.domain(d3.extent(data.map(function(d) { return d.Day; })));
    y.domain([0, d3.max(data, function(d) {
        return d.EC;
    })]);

    svg.append("path") // Add the valueline path.
        .attr("d", valueline(data));

    // Add the black dots
    svg.selectAll("dot")                                    
        .data(data)                                         
        .enter().append("circle")                               
        .attr("r", 5)
        .attr("cx", function(d) { return x(d.Day) })
        //.attr("cx", function(d) { return x(d.Day); })       
        .attr("cy", function(d) { return y(d.EC); }) 

    // Add the axes
    svg.append("g") // Add the X Axis
            .attr("class", "x axis")
            .attr("transform", "translate(0," + height + ")")
            .call(xAxis);

   ...