jquery easyui datagrid 中 数据中某一列 进行两行或三行合并 如何实现

frozenColumns:[[
{field:'ck',checkbox:true},
{title:'code',field:'code',width:80,sortable:true}
]],
columns:[[
{title:'Base Information',colspan:3},
{field:'opt',title:'Operation',width:100,align:'center', rowspan:2 }
],[
{field:'name',title:'Name',width:120},
{field:'addr',title:'Address',width:220,rowspan:2,sortable:true },
{field:'col4',title:'Col41',width:150,rowspan:2}
]],

columns:[
[
{title:'产品',width:80,colspan:2}
],
[
{field:'itemid',title:'Item ID',width:80},
{field:'productid',title:'Product ID',width:120},
{field:'listprice',title:'List Price',width:80,align:'right',rowspan:2},
{field:'unitcost',title:'Unit Cost',width:80,align:'right'},
{field:'attr1',title:'Attribute',width:250},
{field:'status',title:'Status',width:60,align:'center'}
]]

看官网DEMO