请教《javascript语言精粹》一书中关于闭包的一个例子

Question

下面的文字摘自《javascript：The Good Parts》的closure一节，没看懂，秦歌翻译的那本中文版也看了，还是没明白这段文字说的啥？希望各位SF的朋友能用你自己的理解帮我解释一下：为什么第一段代码没有达到目的，不是说内部变量可以读取函数外部变量的吗？读取不到正确的标号，那怎么会弹出节点的数量呢？这个节点数量是怎么获取到的？为什么第二段代码可以修正第一段代码的错误，加一个匿名函数它到底起到了什么作用？It is important to understand that the inner function has access to the actual variables of the outer functions and not copies in order to avoid the following problem:Code View:The add_the_handlers function was intended to give each handler a unique number (i). It fails because the handler functions are bound to the variable i, not the value of the variable i at the time the function was made:Code View:Now, instead of assigning a function to onclick, we define a function and immediately invoke it, passing in i. That function will return an event handler function that is bound to the value of i that was passed in, not to the i defined in add_the_handlers. That returned function is assigned to onclick.