datagrid判断数据是否可以合并并合并单元格

不多说，贴代码：

function _setDefaultMearge() {    var rows = $("#tt").datagrid('getRows');    var len = rows.length;    var preIndex = 0;    for (var i = preIndex; i< len; i++) {        var cityCode = rows[i].CITY_CODE;        var cityCodeNum = 1;        for (var j = i+1; j< len; j++) {            if (cityCode == rows[j].CITY_CODE) {                cityCodeNum++;            } else {                break;            }        }        $('#tt').datagrid('mergeCells', {            index: i,            field: "CITY_NAME",            rowspan: cityCodeNum        });        preIndex = cityCodeNum+i;    }}