how can we show two time bars in the gantt?

hi friend:

        there is a problem,how can  we show two time bars in the gantt? wo want to   compare the plan time bar and the act time bar.

        look forward your response thanks!

Hello,
You can show any HTML elements over the tasks by using the addTaskLayer feature:
https://docs.dhtmlx.com/gantt/api__gantt_addtasklayer.html
Here are examples with the baselines:
https://docs.dhtmlx.com/gantt/samples/04_customization/15_baselines.html
http://snippet.dhtmlx.com/5/ce45fe596