使用“let”和“var”有什么区别？ - What's the difference between using “let” and “var”?

问题：

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

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.我听说它被描述为local变量，但我仍然不太确定它与var关键字的行为有何不同。

What are the differences?.有什么区别？。 When should let be used instead of var ?什么时候应该使用let而不是var ？

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解决方案：

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