LigerUi中Grid控件如何让左侧第一列显示序号

LigerUi中Grid控件如何让左侧第一列显示序号2015-06-28代码示例如下：

var grid = $（"#maingrid"）.ligerGrid（{columns: [{ display: "序号", name: "ID", width: 100, type: "text", align: "left" }, { display: "联系电话", name: "Telephone", width: 100, type: "date", align: "left" },{ display: "负责人", name: "LegalPerson", width: 60, type: "date", align: "left" } ], dataAction: "local", url: "../hanClass&v=5", //【后面的rownumbers:true,加上或去掉】 rownumbers:true,pageSize: 20, sortName: "OrderID",isScroll: false,var grid = $（"#maingrid"）.ligerGrid（{ width: "98%", height: "100%", heightDiff: -10, checkbox: false}）;