[Kos]

C использованием JQuery:

<div id="container_1">
	<div id="element">Hello </div>
</div>
<div id="container_2">
	<div id="element">World!</div>
</div>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript">
	alert($('#container_1').find('#element').text() + $('#container_2').find('#element').text());
</script>