chosen插件 select 替换 option

<div class="col-sm-10">
    <select name="dept_id" id="demo" onchange="subject()" class="chosen-select">
    <option value="">选择部门</option>         
    <option value="1">测试1</option>    
    <option value="2">测试2</option>                    
    </select>
    <span class="help-block m-b-none"></span>
</div>


<script type="text/javascript">

    function subject() {

        let html = '';
        html += "<option value="1">替换1</option>";
        html += "<option value="2">替换2</option>";
        $('#demo').html(html);
        $('#demo').trigger("chosen:updated");//替换后执行updated  重新加载 如果不执行重新加载 select 内容会被替换 但是展示不出来
      

    }
</script>