Any example for drop down on change in AEM 6.2 dialog

Yes,both first and second drop down's are is multi select

If you just need a field toggling you can just go through this:

Toggle fields based on selection in Granite UI dialogs | Adobe AEM Club

So second dropdown is multiselect?    

Hi Susheel,

I am showing static data for second drop down too.

dropdown1  :   canada

                        usa

dropdown2(If I select Canada we have to show like) :  Manitoba,

                    (for usa no drop down to shown )                  British

                                                                                      Columbia

And the values are multi select.

Hi Sandhya,

Where are you going to load the second drop-down from ?