这里输出的x = 1他并没由进行自增操作为什么
```javascript
<script>
function a(){
x= 1
return x++
}
console.log(a())//1
```
这里输出的x = 1他并没由进行自增操作为什么
```javascript
<script>
function a(){
x= 1
return x++
}
console.log(a())//1
```
++在前,先算++,再赋值(return);++在后,先赋值(return)再算++
<script>
function a() {
x = 1
return ++x
}
console.log(a())//2
</script>