Hey sasi,
Please refer below sample.
HTML
CS.aspx
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<iframe id="iFrame" runat="server" src="Default.aspx"></iframe>
</div>
</form>
</body>
</html>
Default.aspx
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript">
window.onload = function () {
window.scrollTo(0, document.body.scrollHeight);
document.getElementById("TextBox1").focus();
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
Welcome To ASPSnippets.com
<asp:TextBox ID="TextBox1" runat="server" />
</div>
</form>
</body>
</html>
Screenshot
