title: how to use tickInterval or step in the highcharts?
body: <p>For example</p>
  
  <p>If i want set the Categories,i can write this code</p>
  
  <p>chart.xAxis[0].setCategories(list.time);</p>
  
  <p>then i want set tickInterval or step in the highcharts</p>
  
  <p>how to use?</p>