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 id="wrap">
<div class="div-1">1</div>
<div class="div-2">2</div>
<div class="div-3">3</div>
</div>
JavaScript
var elements = ['.div-1', '.div-3'];
$(elements.join(', ')).fadeOut(2000);