layui动态修改select的选中项

<div class="layui-form-item">
    <label for="L_name" class="layui-form-label">
        <span class="x-red">*</span>审批类型
    </label>
    <div class="layui-input-inline">
        <select lay-search="" lay-filter="cate_demo" name="cate" id="cate">
            <option value="0">请选择</option>
            <option value="1">入户审批</option>
            <option value="2">发票审批</option>
            <option value="3">完税审批</option>         
        </select>
    </div>
    <div class="layui-form-mid layui-word-aux">
    </div>
</div>      

<div class="layui-form-item">
    <label for="L_name" class="layui-form-label">
        <span class="x-red">*</span>审批人
    </label>

    <div class="layui-input-inline">
        <select lay-search="" lay-filter="admin_user" name="admin_user[]" id="admin_user">
        </select>
    </div>

    <div class="layui-form-mid layui-word-aux">
    </div>
</div> 

<script id="choice_lists" type="text/html">
    {{each list as value i}}
        <option value="{{value.id}}">{{value.nick_name}}</option>
    {{/each}} 
</script>

// 定义锁，true表示锁死，false表示可操作
let lock_flag = false;
layui.use(['jquery','form', 'layer'],

    function () {
        $ = layui.jquery;
        var form = layui.form, layer = layui.layer;

        form.on('select(cate_demo)', function(data){
            $.ajax({
                data        :   {cate:data.value},
                url         :   'get_checker',
                dataType    :   'json',
                type        :   'POST',
                success     :   function(data){ 
                    var art_data = { 
                        list    : data.data
                    };

                    var html = template('choice_lists', art_data);                        
                    //var html = '<option value="2">ru_checker</option><option value="2">ru_checkersss</option>';
                    $('#admin_user').html(html);
                    form.render();            //在layui中重新渲染表单这一步比较重要，部分表单元素需要重新渲染后才能生效，例如select
                },error:function(){
                    layer.alert('接口错误');
                }
            });
        })


        //监听提交
        form.on('submit(add)',
            function (data) {
                if (!lock_flag) {
                    // 上锁
                    lock_flag = true;
                    $("#edit_form").submit();
                }
                return false;
            }
        );
    }
);