var a=1,b=2;
(function () {
console.log(a); //undefined
console.log(b);//2
var a=b=3;
console.log(a);//3
console.log(b);//3
})();
console.log(a);//1
console.log(b);//3
</script>
我完全不知道结果是怎么得到的,被变量的提升和作用域绕晕了,诚恳求助各位好心人,谢谢