Signout using Javascript

STEP1: Put a button from which page we want to signout
<asp:Button ID="btnlogout" Text="signout" runat="server" OnClick="btnlogout_Click" />
and its onclick
response.write("signout.aspx");

signout.aspx

<head runat="server">
<title>Untitled Page</title>
<script type="text/javascript" language="javascript" src="signout.js"></script>
</head>
<body onload="backButtonOverride()">
<form id="form1" runat="server">
<div>
<a href="Login.aspx">signout completely</a>
</div>
</form>
</body>

signout.js

function backButtonOverride()
{
// Work around a Safari bug
// that sometimes produces a blank page

setTimeout("backButtonOverrideBody()", 1);

}

function backButtonOverrideBody()
{
// Works if we backed up to get here
try {
history.forward();
} catch (e) {
// OK to ignore
}
// Every quarter-second, try again. The only
// guaranteed method for Opera, Firefox,
// and Safari, which don't always call
// onLoad but *do* resume any timers when
// returning to a page

setTimeout("backButtonOverrideBody()",500);
}