在计算具有相同类的元素之后通过js添加元素

This one should be quick. I have a simple page that loads reviews dynamically from a web app which are about 33% wide. the problem is that the reviews are of course all different sizes. What I want to do is to count all the elements with the same class, "reviews", AND to add an element to the page AFTER every third element so I can add a separator, full width, empty div to separate each set of three based on the height of the biggest one in the set. I found a way to count the elements already:This one should be quick. I have a simple page