JSFiddle - React, Tailwind, and code Playground
by Nick Craver
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/dot-luv/jquery-ui.css">
<div>
<div>Content</div>
<div>Content</div>
<div>Content</div>
<div>Content</div>
<div>Content</div>
<div>Content</div>
</div>
CSS
.new { border: solid 1px #ddd; padding: 5px; }
JavaScript
var divs = $("div > div");
for(var i = 0; i < divs.length; i+=3) {
divs.slice(i, i+3).wrapAll("<div class='new'></div>");
}