In Malaysia Twitter Political Index, I didn't show legend for the chart because it is ugly. And I don't feel like I want to make an effort to style it. Plus, when you hover on the chart, it will show tooltip with details. So I figured, there's no need for legend.
But, not everyone will hover. They will get confused. I looked at Twitter Political Index, no legend too, instead it just shows the tooltip, I decided to do the same.
It's not hard to figure out, all I had to do was google for it :P I found my answer in this forum (or you can fiddle it here).
I just need to loop the series to get to the last point and refresh tooltip with the points.