js ?typeof

var show=function (x) { ???????????console.log(typeof x); ???// undefined ???????????console.log(typeof 10); ??// number ???????????console.log(typeof ‘abc‘); // string ???????????console.log(typeof true); ?// boolean ???????????console.log(typeof function () {}); ?//function ???????????console.log(typeof [1, ‘a‘, true]); ?//object ???????????console.log(typeof { a: 10, b: 20 }); ?//object ???????????console.log(typeof null); ?//object ???????????console.log(typeof new Number(10)); ?//object ??????return 1; ???????}console.log( show instanceof Object)console.log( show())var fn=function(){}console.log( fn instanceof Object)

var dd="就ask打开";console.log(isNaN( parseInt(dd)));