SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<div id="bigBadDiv">
<div class="head">
    blabla
</div>

<div class="contents">
    <div class="1">
        <div id="432" class="item "></div>
        <div id="45" class="item selected"></div>
        <div id="86" class="item "></div>
        <div id="3" class="item "></div>
    </div>

    <div class="2">
        <div id="443" class="item"></div>
        <div id="867" class="item selected"></div>
        <div id="43" class="item selected"></div>
        <div id="98" class="item selected"></div>
    </div>


    <div class="3">
        <div id="423" class="item selected"></div>
        <div id="167" class="item "></div>
        <div id="4453" class="item "></div>
        <div id="944" class="item "></div>
    </div>
</div>

<div class="footer">
    blabla
</div>
</div>

CSS

div { padding: 10px; border: solid 1px #ddd; }

JavaScript

$('#bigBadDiv .selected').css({'backgroundColor':'red'});

var ids = $('#bigBadDiv .selected').map(function() { return this.id; }).get();

alert(ids);