layui动态生成下拉列表

<select name="deptmgr" lay-filter="FirstSelect" id="FirstSelect" lay-search="">
                    <#--此处动态生成select-->
                    </select>


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//监听头部工具事件
table.on("toolbar(deptTable)", function (obj) {
    switch (obj.event) {
        case 'add':
            var FirstSelect = $("#FirstSelect");
            commonFun.loadDeptSelect(FirstSelect);//加载后台数据，渲染select
            openAddFirstDept();//打开添加一级部门弹出层
            break;
        case 'batchDelete':
            layer.confirm('真的删除么?<br/>(含有子部门的将无法删除...)', function (index) {
                layer.close(index);
                //向服务端发送删除指令
                batchDeleteDept();//执行批量删除函数
            });
            break;
    }
    ;
});

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//加载后台数据，渲染到select中
var commonFun = {
    //canshu:要渲染的select的jquery对象
    loadDeptSelect: function (canshu, mgr) {

        var option = "<option value = ''>请选择</option>";
        $.post("getComEmp", {'oldDeptmgr': mgr}, function (res) {

            console.log(res);
            console.log(mgr);

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

                option += "<option value = '" + res[i].empno + "' ";
                if (res[i].empno == mgr) {
                    option += "selected";
                }
                option += ">" + res[i].empname + "</option>";
                canshu.html(option);
            }
            form.render('select');//重新渲染select
        }, "json");
    }
};
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//控制层

//获取普通员工和当前部门经理的的信息--普通员工，职位编号为016
@RequestMapping("/getComEmp")
@ResponseBody
public List<Emp> getComEmp(String oldDeptmgr) {

    EmpExample example = new EmpExample();
    EmpExample.Criteria criteria = example.createCriteria();
    criteria.andPosinoEqualTo("016");
    List<Emp> emps = null;
    Emp nowMgr = null;
    try {
        //查询当前部门是否存在部门经理
        nowMgr = empService.selectByPrimaryKey(oldDeptmgr);
        //System.out.println("查询当前部门是否存在部门经理:" + nowMgr);
        emps = empService.selectByExample(example);
        if (nowMgr != null) {
            emps.add(nowMgr);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return emps;
}