摘要: ```javascript //如果使用let,声明的变量仅在块级作用域内有效 { var a = 1; let b = 2; } console.log(a); // 1 console.log(b); // Uncaught ReferenceError: b is not defined va 阅读全文
posted @ 2016-06-29 17:53 SmallW 阅读(261) 评论(0) 推荐(0)