Js Why can't you see the variable from the staple?

[carriann]

'use strict';
let numberOfFilms;
function start() {

numberOfFilms = +prompt('Сколько фильмов вы уже посмотрели', '');
while (numberOfFilms == '' || numberOfFilms == null || isNaN(numberOfFilms)) {

numberOfFilms = +prompt('Сколько фильмов вы уже посмотрели', '');

}

}
start();

[inna]

The "use strict" warning.
"use strict" should be declared separately in each function.

(function () {
   'use strict';
   // this function is strict...
}());

If you don't like it, you can turn it off in jshint. /*jshint strict:false */♪ https://stackoverflow.com/questions/4462478/jslint-is-suddenly-reporting-use-the-function-form-of-use-strict

On prompt account:
This has nothing to do with "use strict." It's because you're trying to cause a purely browser function. prompt Environment node.js♪ There's no such function in the night, because she's responsible for calling the question in the window. Browser♪