[javascript/*] typeof is an operator and not a function/method - fix usag...

The usage of `typeof` in all JS demos is misleading:
```javascript
typeof(foo);
```
Although working just as expected this might lead to the conclusion that typeof is a method. Yet it is an operator: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof and should/can therefore be used **without** parens:

```javascript
typeof foo;
```