代码格式测试

 <div class="layui-form-item">
                    <label for="unit_price" class="layui-form-label">
                        <span class="x-red">*</span>购买单价
                    </label>
                        <div class="layui-input-inline">
                            <select id="unit_price" name="unit_price">
                            <option value="" selected="">请选择</option>
                            <option value="1">1元</option>
                            <option value="10">10元</option>
                            <option value="100">100元</option>
                            </select>
                        </div>
        </div>

        <!-- 总需人次 = 商品价格/购买单价 -->
        <div class="layui-form-item">
            <label for="max_buy" class="layui-form-label">
                <span class="x-red">*</span>总需人次
            </label>
            <div class="layui-input-inline">
                <input type="text" id="max_buy" name="max_buy"
                       autocomplete="off" class="layui-input" disabled>
            </div>
        </div>


       <!--  <div class="layui-form-item">
            <label for="user_max_buy" class="layui-form-label">
                限购单数
            </label>
            <div class="layui-input-inline">
                <input type="text" id="user_max_buy" name="user_max_buy"
                       autocomplete="off" class="layui-input">
            </div>
            <div class="layui-form-mid layui-word-aux">
                默认为0，不限购
            </div>
        </div> -->

        <div class="layui-form-item">
            <button  class="layui-btn layui-btn-small" lay-filter="add" lay-submit="">
                确认添加
            </button>
        </div>
    </form>


<script src="/js/x-layui.js" charset="utf-8"></script>
<script>
    layui.use(['form','layer'], function(){
        $ = layui.jquery;
        var form = layui.form();
       
        //监听提交
        form.on('submit(add)', getSubmitForm('{:url("admin/activity/save")}', {}));

        //计算总人次
            $('#unit_price').change(function (){
            var unit_num = $(this).val();
            var gprice = $('#good_marketprice').val();
            console.log(unit_num, gprice);
            $('#max_buy').val(Math.ceil(gprice/unit_num));
        });


    });

    function setGoods(good_id, goods_name,good_marketprice) {
        $('#good_id').val(good_id);
        $('#goods_name').val(goods_name);
        $('#good_marketprice').val(good_marketprice);

    }
</script>