# JavaScript how to create persistent variable

First method is to return a function inside parent function. Note that the inner function has access to private property of parent.

```js
const incr=(function(v) {
	return function() {
  	  return ++v;
  }
})(100);

console.log(incr());  //101
console.log(incr());  //102
console.log(incr());  //103
```

Another way is to define static properties directly.

```js
function f() {}

f.counter=0;
f.incr=function() {
	console.log(f.counter++);
}

f.incr();	//0
f.incr();	//1
f.incr();	//2
f.incr();	//3
```