苦笔的博客

在函数中使用this function foo(c, d) { return this.a + this.b + c + d } global.a = 3 global.b = 4 // foo执行时，this没有明确的指向，默认指向全局对象global // nodejs中是global，browser中是window foo(3, 4) // 14 ...

浏览器全局环境（global context） this === window // true

定义 A closure is the combination of a function and the lexical environment within which that function was declared. This environment consists of any local variables that were in-scope at the time ...

1 定义 // 4种定义方式 new Date().toLocaleString(); // 2018-1-10 20:32:12 // new Date(milliseconds),3年约等于11次方毫秒 new Date(0).toLocaleString(); // 1970-1-1 08:00:00,不知道这是个什么日子 new Date(1515

Number.MAX_VALUE Number.MIN_VALUE Number.MAX_SAFE_INTEGER Number.MIN_SAFE_INTEGER Number.EPSILON ES采用Binary64 0.1 + 0.2 =