###08 插入移除操作
###08 Insert Removal operation
> https://segmentfault.com/a/1190000004896630
本节介绍的ms-if指令与ms-visible很相似，都是让某元素“看不见”，不同的是ms-visible是通过CSS实现，ms-if是通过移除插入节点实现。
This section describes the `ms-if` command and `ms-visible` is very similar, are to make an element "invisible", the difference is that `ms-visible` is achieved through the CSS, `ms-if` is to remove the insert node.
ms-if的用法与1.×时别无二致，只要值是真，就插入，为假时，就在原位置上替换为一个注释节点做占位符。
The use of `ms-if` and 1. × no different, as long as the value is true to insert, when false, in the original location to replace a node to do a placeholder comment.
> 注意： 在avalon1.*中，存在一个叫ms-if-loop的辅助指令，这个在2.0移除了，这个直接使用filterBy过滤器就能实现相似功能。
>Note: In avalon1. *, There is a helper instruction called `ms-if-loop`, which is removed in 2.0. This is done using filterBy filters.
ms-if
这是比较输出结果:{{@object.id != null}}
这是visible的:
{{@object.message}}
这是if的:
{{@object.message}}
现在我们用ms-if重新做一下切换卡吧
Now we use `ms-if` to do something to switch cards
ms-if