城市/区域 二级联动下拉菜单

js 代码

function getarealist(res1,res2)
     {
         var cityid = res1.options[res1.selectedindex].value;
         res2.length=0;
         var ds = property_default.getarea(cityid).value;
         if(ds != null&& typeof(ds) == "object" && ds.tables != null)
         {
            if(res1.selectedindex != 0)
            {                
                for(var i=1; i<ds.tables[0].rows.length; i++)
                {
                    var name=ds.tables[0].rows[i].areaname;
                    var id=ds.tables[0].rows[i].areaid;
                    res2.options.add(new option(name,id));
                }
            }
            else
            {
                res2.options.add(new option("选择区域","0"));
            }
        }
     }

cs 代码

[ajaxpro.ajaxmethod]//获得区域数据
    public dataset getarea(int cityid)
    {
        string str = "select * from ktv_area where cityid=" +  cityid;
        dataset ds = database.exesqlda(str);
        return ds;
    }

private dataset getdata()
    {
        string str = "select * from property_city";
        dataset ds = database.exesqlda(str);
        return ds;
    }