Certo che lo è.
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function pippo() {
oColl = document.getElementsByTagName('DIV');
for (i=0;i<oColl.length;i++) {
curObj = oColl.item(i);
if (curObj.className == "mia_classe") {
alert(curObj.id);
}
}
}
//-->
</script>
</head>
<body onload="pippo()">
<div id="livello_1" class="mia_classe"><div>
<div id="livello_2" class="mia_classe"><div>
<div id="livello_3"><div>
<div id="livello_4" class="mia_classe"><div>
</body>
</html>