Sums of several columns at the footer of a table

Hello,

I tried to have sums of several columns at the footer of my table. I tried differents options but without success.

I tried this : https://datatables.net/examples/advanced_init/footer_callback.html
but I can only have the total of one column.

I tried this: https://datatables.net/examples/plug-ins/api.html
I have all the column like I want with the sum of the sorting but there are buttons. Is there a solution to have this method with sum in the footer of columns?

I tried others thinks too but nothing good for what I want I'm a beginner and Javascript is very difficult for my at the moment.

Thanks for advance.

Delph