使用“let”和“var”有什麼區別？ - What's the difference between using “let” and “var”?

問題：

ECMAScript 6 introduced the let statement . ECMAScript 6 引入了let語句。

I've heard that it's described as a local variable, but I'm still not quite sure how it behaves differently than the var keyword.我聽說它被描述爲local變量，但我仍然不太確定它與var關鍵字的行爲有何不同。

What are the differences?.有什麼區別？。 When should let be used instead of var ?什麼時候應該使用let而不是var ？

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解決方案：

參考一： https://stackoom.com/question/3CEV
參考二： What's the difference between using “let” and “var”?