<input type="button" value="關閉窗口" onclick="javascript:window.close()">  

<input type="button" value="關閉窗口" onclick="window.close()">  

<input type="button" value="關閉窗口" onclick="java:window.close()">

<a href="logout.jsp" class="a1">退出</a>

<%
    session.invalidate();
    response.sendRedirect("index.jsp");
%>