Try this,
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script language="javascript" type="text/javascript">
$(function () {
alert($("#div2").html());
$("#div2").html("<input type='text' id='textbox1' value='Hello!!' />");
});
<div id="div2"></div>