<body >
http://msdn.microsoft.com/workshop/author/dhtml/reference/events/onbeforeunload.asp?frame=true
body 的onbeforeunload = "return 'YOUR MESSAGE HERE'"
To see a world in a grain of sand.
And a heaven in a wild flower
Hold infinity in the palm of your hand.
And eternity in an hour
一花一世界
一沙一天堂
掌中握无限
霎那成永恒
