protected void txtEmail_TextChanged(object sender, EventArgs e)
{
if (IsPostBack)
        {
            string str = txtEmail.Text.Trim();
            string[] name = str.Split('@');
            string s = name[0].ToString();
  if (name.Length > 1)
            {
                txtLoginName.Text= name[0];
            }
            else if (s == name[0])
            {
                lblMessage.Text = "";
                lblMessage.Text = "Invalid email";
                txtLoginName.Text = "";
                txtPwd.Text = "";
            }
}
}
}