</head>
<body>
<div id="my" class="myClass"/>
<script>
var obj = document.getElementById('my');
alert(obj.className);
</script>
</body>
<body>
<div id="my" class="myClass"/>
<script>
var obj = document.getElementById('my');
alert(obj.className);
</script>
</body>
alert(obj.getAttribute('class'))