摘要: if(!("isNaN" in Number)){ Number.isNaN = function(val){ return typeof val 'number' && isNaN(val) } } var arr = [NaN]; arr.indexOf(NaN);//-1 arr.includ 阅读全文
posted @ 2023-03-10 14:56 flybaby诺诺 阅读(53) 评论(0) 推荐(0)
摘要: 1.typeof null(object) NaN(number) ducument.all(undefined) 注意:暂时性死区(ES6) function log(){ typeof a let a = 10 } log();// ReferenceError ReferenceError: 阅读全文
posted @ 2023-03-10 14:37 flybaby诺诺 阅读(17) 评论(0) 推荐(0)