title: Invalid value for <path> attribute
body: <p>I see other posts with this problem but I just can't seem to solve it. I am new to d3 and am trying to load some data into a line graph, but i keep getting the error </p>
  
  <p><code>Invalid value for &lt;path&gt; attribute d="MNaN,250LNaN,71.05263157894737LNaN,55.26315789473685</code></p>
  
  <p>I have setup everything like in an example (which worked), but this isn't working for some reason. I am getting data back from a webservice as a list of the following form: Date="1/1/2014" NumberOfActive=1 (Example). I have tried using the parse functions but they don't really work. Here is my code:</p>
  
  <pre><code>var data;
          var margin = { top: 20, right: 20, bottom: 30, left: 50 },
              width = 1000 - margin.left - margin.right,
              height = 300 - margin.top - margin.bottom;
  
          function parseDateForViewing(d) {
              return d3.time.format('%b %Y')(d3.time.format('%m/%d/%Y').parse(d));
          }
  
          function parseDate(d) {
              return d3.time.format('%c')(d3.time.format('%m/%d/%Y').parse(d));
          }
  
          var x = d3.time.scale()
              .range([0, width]);
  
          var y = d3.scale.linear()
              .range([height, 0]);
  
          var xAxis = d3.svg.axis()
              .scale(x)
              .orient("bottom");
  
          var yAxis = d3.svg.axis()
              .scale(y)
              .orient("left");
  
          var line = d3.svg.line()
              .x(function (d) { return x(d.Date); })
              .y(function (d) { return y(d.NumberOfActive); });
  
          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 + ")");
  
  
          $.ajax({
              type: "POST",
              url: "Dashboard.aspx/GetActiveLoansData",
              data: '',
              contentType: "application/json; charset=utf-8",
              dataType: "json",
              success: function (thedata) {
                  var d = thedata.d;
                  data = thedata.d;
  
                  var _len = d.length;
                  var post, i;
  
                  for (i = 0; i &lt; data.length; i++) {
                      d = data[i];
                      var t = parseDate(d.Date);
                      var s = d.Date;
                      x.domain(d3.extent(data, function (d) { return d.Date; }));
                      y.domain(d3.extent(data, function (d) { return d.NumberOfActive; }));
  
                      svg.append("g")
                          .attr("class", "x axis")
                          .attr("transform", "translate(0," + height + ")")
                          .call(xAxis);
  
                      svg.append("g")
                          .attr("class", "y axis")
                          .call(yAxis)
                          .append("text")
                          .attr("transform", "rotate(-90)")
                          .attr("y", 6)
                          .attr("dy", ".71em")
                          .style("text-anchor", "end")
                          .text("Closed Loans");
  
                      svg.append("path")
                          .datum(data)
                          .attr("class", "line")
                          .attr("d", line);
                  }
              }
          });
  </code></pre>