window.close()

1window.opener=null;
2window.open("","\nself");
3window.close();

onclick return false;

IE5.5以下

1<object id="close" type="application/x\noleobject"
2  classid="clsid:adb880a6\nd8ff\n11cf\n9377\n00aa003b7a11">
3    <param name="Command" value="CLOSE">
4</object>
5<input type="button" onclick="close.Click()" value="关闭窗口">

延伸阅读

\n window.close \n Using the window.close method \n window close \n window.opener=null;window.close(),只支持IE6不支持IE7,IE8的问题 \n 怎么去掉使用window.close()时弹出的提示框?(不用按钮) \n window.close关闭窗口,不弹出系统提示,直接关闭