<script>
var a = 1;
var b = '哈';
var c = ['2', '1'];
var d = {
bb: 'dafa'
};
var e = undefined;
var f = null;
var g = true;
// typeof
console.log(typeof a)//number
//instanceof方法判断数据类型
console.log(e instanceof Object)//false
// 用于判断是否对象类型,是的话返回true，否则返回false
console.log(d instanceof Object)//true
// toString.call()方法判断数据类型
console.log(toString.call(a)); //[object Number]
console.log(toString.call(b)); //[object String]
console.log(toString.call(c)); //[object Array]
console.log(toString.call(d)); //[object Object]
console.log(toString.call(e)); //[object Undefined]
console.log(toString.call(f)); //[object Null]
console.log(toString.call(g)); //[object Boolean]
</script>
