Delete Last row from dhtml grid

I want to delete last row from grid.



When I Click on button only last row removed from grid.



I want to use function



mygrid.deleteRow(mygrid.getRowId(mygrid.rowsCol.length-1),mygrid.row);





The more simple|stable approach will be

    mygrid.deleteRow(mygrid.getRowId(mygrid.getRowsNum()-1));