How to get checked parent and child node in treeview control asp.net

Hi All,

I have on tree view  like below (dyanmic : Populate on demand : true)

I have append check box on each tree node (both for parent and child )

 Level1 :

           :Level1.1

           :Level 1.2

                          :Level 1.2.1 

Level 2 : 

I need all checked tree node value on button click .

using jquery or code behind 

Thanks