title: jqPlot with DateAxisRenderer and ajax
body: <p>I'm running into difficulties trying to combine DateAxisRenderer and ajax on a jqPlot chart. The code below does not produce any errors but it creates a chart with no gridlines, no labels on the y axes, and no data points plotted. There is just a blank white chart background with two x axis labels both saying Dec 31, 69.</p>
  
  <p>If I swap out the ajaxDataRenderer and use data from an array like what is done in this example (<a href="http://www.jqplot.com/tests/date-axes.php" rel="nofollow">http://www.jqplot.com/tests/date-axes.php</a>) everything renders correctly.</p>
  
  <p>Here is my Javascript:</p>
  
  <pre><code>var ajaxDataRenderer = function(url, plot, options) {
     var ret = null;
     $.ajax({
          async: false,
          url: url,
          type: "GET",
          dataType:"json",
          success: function(data) {
              ret = data;
          },
          error:function (xhr, ajaxOptions, thrownError){
              alert(xhr.responseText);
          }
     });
     return ret;
  };
  
  var jsonurl = "http://localhost:8080/chartdata";
  var plot2 = $.jqplot('chart2', jsonurl, {
      title:'Customized Date Axis',
      dataRenderer: ajaxDataRenderer,
      axes:{
          xaxis:{
             renderer:$.jqplot.DateAxisRenderer,
             tickOptions:{formatString:'%b %#d, %y'}
          }
      }
  });
  </code></pre>
  
  <p>The JSON being returned from <code>jsonurl</code> looks like:</p>
  
  <pre><code>[["2008-09-30 4:00PM",15],["2008-10-30 4:00PM",8],["2008-11-30 4:00PM",17],["2008-12-30 4:00PM",10]]
  </code></pre>
  
  <p>Any ideas would be much appreciated!</p>