title: Role on dynamic google chart (interval)
body: <p>How can I use this: <a href="https://developers.google.com/chart/interactive/docs/roles" rel="nofollow">https://developers.google.com/chart/interactive/docs/roles</a> if I populate the graph dynamically?</p>
  
  <p>This is part of my code:</p>
  
  <pre><code>...
  data.addRows(dates.length);
  for (i = 0; i &lt; dates.length; i++){
      if (i!=0){
          data.setValue( i, 0, new Date(dates[i]) ); 
          temp = graph[dates[i]];
          var j = 0;
          if (temp){
              for (j = 0; j &lt; groups.length; j++){
                  if ( groups[j] in temp){
                      var volume = parseFloat(temp[groups[j]]);
                      console.log(i + '  ' + j + '  ' + volume);
                      data.setValue( i, j+1, volume )
                  }
              }
          }
      }else{
          data.setValue( i, 0, new Date(dates[i]) ); 
          var j = 0;
          for (j = 0; j &lt; groups.length; j++){
              data.setValue( 0, j+1, 0 )
          }
      }
  }
  ...
  </code></pre>
  
  <p>After I set the value with 'data.setValue', how can I set also the role? (I need for the interval value) Something like 'data.setRole' would be wonderful!! :-)</p>