<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function () {
$(function () {
$('#txt2').focus(function () {
$(this).animate({ height: 100 }, 500);
});
$('#txt2').blur(function () {
$(this).animate({ height: 30 }, 500);
});
});
});
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:TextBox ID="txt2" rows="3" cols="12" style="height: 30" runat="server"></asp:TextBox>
<textarea id="txt1" rows="3" cols="12" style="height: 30"></textarea>
</div>
</form>
</body>
</html>
CHeck your Code where you wrong
