Question1: Why the legend of series 2 and 3 dose NOT show dot/dash line? I need to make it consistent with the chart.
Changing legend line dash type is not possible as of now. However, you can workaround this by setting the legendMarkerColor to white and legendMarkerType to triangle. Please take a look at this jsfiddle
Question2: Is there any way I can group legend make stype them separately. e.g. I want to make series 1, 2,3 legend virtically aligned to the left bottom and label 1 and 2 vertically aligned to the right bottom.
Sorry, it’s not possible to group legends as of now. All legends will be positioned together.
Question3: All my data has integer as x value, why it automatically calculated to interval as 0.5? I cannot specify interval to a specific integer because it is dynamic based on data comes in. But I need x value always calculated and displayed as integer. How can I implement this?
Axis interval depends on the axis range, number of ticks, as well as width of the chart, which means more the width of the chart interval will be less and lesser the width of chart interval will be more. You can try setting interval and update it based on the new dataPoint x-values added.