Getting last character of variable?

I tried to get the last character of a variable. 'var' is getting q1d from that select.

I want to get d in qwer var. Maybe its duplicated question but I am asking why those doesn't work ?

> slice, substr, split ?

      var qwer=$('.chkbox[value="' + $('#tablebody tr:last td:last-child').text() + '"]').attr("id");
      alert(qwer);// alerting q1d
      qwer.slice(-1); // i tried slice, substr, split but all same 
      alert(qwer);// alerting still q1d