带有奇偶类的Javascript DOM操作

I have HTML like this

我有这样的HTML

<div class="oddeven">
    <p id="p1" class="odd">Lorem ipsum</p>
    <p id="p2" class="even">dolor sit amet</p>
    <p id="p3" class="odd">consectetur adipiscing</p>
    <p id="p4" class="even">sed do</p>
    <p id="p5" class="odd">eiusmod tempor</p>
    <p id="p6" class="even">incididunt ut</p>
</div>
<button class="btnClick">Click</button>
<div class=