title: conditional marker colors in highcharts
body: <p>I'm using Highcharts and I want to fill markers in line chart with different colors. For example: when variable "a" is 1 then fill marker with red else fill with green. Is it possible to do that?</p>
  
  <p>Here is the code: <a href="http://jsfiddle.net/u9EzG/" rel="noreferrer">http://jsfiddle.net/EnyCJ/1/</a></p>
  
  <p>I was trying to do that with formatter but it doesn't work. Any suggestions?</p>
  
  <pre><code>var a=1;
  
  plotOptions: {
   series: {
    marker: {
     fillColor: {
      formatter: function () {
        if (a == 1) {
         return 'red'
        } else {
         return 'green'
        }
      }
     },
    lineWidth: 2,
    }
   }
  },
  </code></pre>