有关变量提升知识请戳这里:JavaScript中变量提升(声)
1.
fn()
function fn() {
console.log(1)}
fn()
function fn() {
console.log(2)
}
fn()
var fn = function () {
console.log(3)
}
fn()
function fn() {
console.log(4)
}
fn()
function fn() {
console.log(5)
}
输出:5
5
5
3
3
图解: