v-show 动画

<transition name="fade">
	<span v-show="isShow">动画效果</span>
</transition>

.fade-enter-active, .fade-leave-active {
    transition: opacity .25s
 }
 .fade-enter, .fade-leave-to /* .fade-leave-active in <2.1.8 */ {
    opacity: 0
}