问题
With the new keyword let for declaration of variables in javascript ES6, I can no longer think of good reasons to use var. So far, I have been doing just that and I do not see any disadvantage of using let ALL THE TIME.
What are good reasons to use var today? Is it a good practice to use let all the time today?
回答1:
IMO there is no definite advantage of using var over let, other than for its scope. One reason might be to support older browsers perhaps (if you don't plan to use an ES6 to ES5 compiler like Babel).
来源：https://stackoverflow.com/questions/41031342/what-are-some-reasons-to-use-var-instead-of-let-in-javascript