title: How to set tick length in y-axis to 0 or remove tickline from y axis in highchart?
body: <p>for x axis 'tickLength: 0' is working and I can remove the tick from x-axis label,but same thing not working for y axis. Please suggest me the right way to remove the y axis tick line. </p>
  
  <pre><code>$(function () {
  Highcharts.setOptions({
      colors: ['#C9F4F4']
  });
  $('.container').highcharts({        
      chart: {
          type: 'area',          
      },
      credits: {
          enabled: false
      },
      title: {
          text: ''
      },
      xAxis: {
          categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'June', 'Jul','Aug','Sep','Oct','Nov','Dec'],
          tickmarkPlacement: 'on', 
          overflow:'false',
          gridLineWidth: 1,
          //tickLength: 0,
          startOnTick:true,
          title: {
              enabled: false
          }
      },
      yAxis: {             
          min: 100, 
          max: 1000,
          tickInterval: 100,                           
          gridLineWidth: 1,               
          title: {
              enabled: false
          },
          labels: {                                
              formatter: function () {
                  return this.value;
              }
          }
      },
      tooltip: {
          shared: true, 
          formatter: function () {
              return this.y;
          }
      },
      plotOptions: {
          series: {                
              lineColor: '#00CFCF',
              lineWidth: 1,
              marker: {
                  lineWidth: 1,
                  lineColor: '#00CFCF',
                  enabled: false,                    
              }
          }
      },
      navigation: {
          buttonOptions: {
              enabled: false
          }
      },
      series: [{
          name: 'Asia',
          data: [502, 635, 809, 947, 900, 1000, 1000,200,750,630,400,75]
      }]
  });
  </code></pre>
  
  <p>});</p>
  
  <p>here is the <a href="http://jsfiddle.net/sojitrar88/xznu95mv/3/" rel="nofollow">JSFiddle</a></p>