变量类型
2017-10-06 本文已影响0人
乍暖还寒2002
var a = 12;
console.log(typeof a); //number
a ='aaaa';
console.log(typeof a);//string
a = true;
console.log(typeof a);//boolean
a = function (argument) {
aler('11');
}
console.log(typeof a);//function
a = document;
console.log(typeof a);//object
var b;
console.log(typeof b);//undefined
//undefined分两种情况
//1.真的没有定义
//2.虽然定义，但是没有给值
