js各种关键字

分类: 文章 • 2024-06-21 23:29:22

typeof: 把类型信息当作关键字返回，可以用来验证变量的类型。返回值有几种"number," "string," "boolean," "object," "function," 和 "undefined."但是对于null和arr返回的都是objct，故无法准确判断对象、数组的类型

num | 0 取整操作