protected void btnExit_Click(object sender, EventArgs e)
{
ClientScriptManager CSM = Page.ClientScript;
if (!ReturnValue())
{
string strconfirm = "<script type='text/javascript'>if(window.confirm('Are you sure?')){window.location.href='Default.aspx'}</script>";
Page.ClientScript.RegisterStartupScript(this.GetType(), "Confirm", strconfirm, false);
}
}