疑问汇总（也许日后能慢慢搞明白）：

疑问1：位于第三章，26页

The first concept to understand is that everything is case-sensitive; variables, function names, and operators are all case-sensitive, meaning that a variable named test is different from a variable named Test. Similarly, typeof can’t be the name of a function because it’s a keyword (described in the next section); however, typeof is a perfectly valid function name.

 

推荐的开发习惯：

1：每个语句都以分号结束。

2：if语句用花括号包住。

3：不要使用关键字和保留字。

 

经验总结：

1，let在一些低版本的手机上还是不支持的。