function exportExecl(obj) {

            var cfs = $(obj).datagrid('getColumnFields'); //这是获取到所有的Fields

            //得到title名

            var colName = [];

            for (i = 0; i < cfs.length; i++) {

                var col = $(obj).datagrid("getColumnOption", cfs[i]);

                colName.push(col.title);//把TITLEPUSH到数组里去

            }

            console.log(colName);

        }