I. .slide-one.animate-in ---> 追加 追加
Ⅱ．.slide-one ---> 削除 追加
HTML:
<ul class="animation-canvas">
<li class="slide-one">slide-one</li>
</ul>
<div>
HTML アクティブ:
<ul class="animation-canvas">
<li class="slide-one animate-in">slide-one</li>
</ul>
<div>
JS:
$('ul.animation-canvas li.animation-in').append('<div class="iebox">test</div>');