[SOLVED] How to notify iframe in the parent window that all the scripts of yandex map has been loaded?

How to notify iframe in the parent window that all the scripts of yandex map has been loaded?

There is a cross-window iframe, which contains a link to index.php from another server, which, in turn, has a Yandex maps api script (see below). How to make sure that this script chain is fully loaded? I'm trying the following way:

 <script>
            function loaded() {
                window.parent.postMessage('loaded', '*');
            }
        </script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js" type="text/javascript"></script>
        <script src="https://api-maps.yandex.ru/2.1/?apikey=bla-bla-bla&lang=ru_RU" type="text/javascript" onload="loaded()"></script>

The message arrives, but the map is not displayed. Which, in my opinion, means incomplete loading of scripts.

Chain of yandex map scripts

Solution