解决了。原来是PhoneGap 1.3中的一个错误，修复了昨天发布的版本1.4（！）。

Solved it. Turned out to be a bug in PhoneGap 1.3 which was fixed in version 1.4 released yesterday(!).

从发行说明：

固定CB-42 - MediaPlaybackRequiresUserAction现在可以设置为NO

Fixed CB-42 – MediaPlaybackRequiresUserAction can now be set to NO