Since the body of the callback is trivial here, we've defined the entire function inline as an anonymous subroutine.

由于这个回调程序体很小，所以我们将整个函数内嵌为一个匿名子例程来完成。

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Global or inline scripts, which are scripts that are not part of an event-handling subroutine or function, are executed immediately.

立即执行全局或内联脚本，这些脚本不是事件处理子例程或函数的一部分。

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