我发现让Google文档查看器处理iframe的唯一方法是：

The only way I've found to get the Google Docs Viewer to work in an iframe is:

<iframe src="https://docs.google.com/viewer?srcid=[YOUR_FILE'S_ID_HERE]&pid=explorer&efh=false&a=v&chrome=false&embedded=true" width="800" height="600" style="border: none;"></iframe>