SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<div class="content">
<form>
<div class="item">
blablaform stuf
</div>
<div class="item">
blablaform stuf
</div>
<div class="item">
blablaform stuf
</div>
<div class="item">
blablaform stuf
</div>
</form>
</div>

CSS

.item { border: solid 1px #ddd; }
.wrapper { border: solid 1px red; padding: 2px; }

JavaScript

var elems = $(".content div.item");
for(var i = 0; i < elems.length; i+=2) {
  elems.slice(i, i+2).wrapAll("<div class='wrapper'></div>");
}