简单的浮动代码，纯js代码，但不符合w3c标准，在有些HTML规范下不可行，
例如：
具体原因不清楚，待大神告知。
完整代码如下（字母为背景测试）：
带关闭按钮的浮动窗口 关闭我是一个简单的浮动窗口advadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadvadvadvadddddddddddddddddddddddadvadvadadvadva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