Change datasource & reloadGrid dynamically jq|Grid

 $.ajax({

        type: "POST",
        url: '../../Journal/load_journal_voucher',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (msg) {
                     if (msg != null) {
                gidData = msg;

                var g = $("#JournalGrid");
                g.setGridParam({ data: gidData });
                g[0].refreshIndex();
                g.trigger("reloadGrid");

            }
        }
    })