aiaks,
<html>
<head><title>...</title></head>
<body>
<div><p class="text_class" style="font-family:arial">text</p></div>
<script>
window.onload = function () {
alert(document.body.children[0].innerHTML);
document.body.children[0].children[0].removeAttribute("class");
document.body.children[0].children[0].removeAttribute("style");
alert(document.body.children[0].innerHTML);
}
</script>
</body>
</html>