JavaScript获取select下option选中的页面值

HTMl

    <form class="layui-form" id="form_addUser">
            <div class="layui-form-item">
                <label class="layui-form-label">选择班级</label>
                <div class="layui-input-block">
                    <select name="class_cate_id" lay-verify="required">
                        <option value=""></option>
                        {{each}}
                        <option value="{{$value.id}}">{{$value.class_name}}</option>
                        {{/each}}
                    </select>
                </div>
            </div>
    </form>

JavaScript

var tempId = $('#form_addUser [name = class_cate_id] option:selected').text();
console.log(tempId);