摘要: //1.数学运算的时候 var num = +'123'; var num1 = -'123'; var num2 = '123'/1; console.log(typeof num1) console.log(typeof num) //2.new 运算符 var num = new Number 阅读全文
posted @ 2017-01-07 07:14 天空· 阅读(1374) 评论(0) 推荐(0)