title: HighCharts.js is not rendering chart under IE8
body: <p>I am using HighCharts together with Python to dynamically create charts. All works fine, however I get <code>cannot read property "0" of undefined</code> exception under IE8. Unfortunetly my client want it to work under IE8 as well. So heres the code of the main function:</p>
  
  <pre><code>function generateChart(series) {
      var chart = new Highcharts.Chart({
          chart: {
              renderTo: 'company_chart',
          },
          xAxis: {
              type: "datetime",
          },
          yAxis: [{
              title: {
                  text: "T1",
                  },
              },{
              title: {
                  text: "T2",
                  },
              },
              opposite: true,
          }],
          plotOptions: {
              series: { shadow: false },
              column: { shadow: false, },
          },
          series: series
      });
  );
  </code></pre>
  
  <p>Now my ajax request returns some data and I store it in the variable like this:</p>
  
  <pre><code>chart_data = [
      {
          type: "spline",
          color: '#ff0000',
          yAxis: 0,
          data: dataT1,
      },
      {
          type: "column",
          color: '#0000ff',
          yAxis: 1,
          data: dataT2,
      }
  ];
  </code></pre>
  
  <p>After that I call <code>generateChart(chart_data);</code>. The format of variables <code>dataT1</code> and <code>dataT2</code> is fine, since it works under every other browser. For example <code>dataT1</code> may look like this:</p>
  
  <pre><code>dataT1 = [ [1325721600000,1.64],
             [1325635200000,1.64],
             [1325548800000,1.7],
             [1325462400000,1.7],];
  </code></pre>
  
  <p>But still the exception is thrown under IE8. Any ideas how to fix this?</p>