Отложная загрузка карты #Yandex

lazy-map.js

jQuery(document).ready(function($) {
    /** @let Is map already enabled */
    var mapEnabled;
    /** @let append in this wrepper || watch then scroll on viewport */
    var $mapWrapper = $('.footer-contacts__map');
    /** @const wrapper top position from start page */
    var mapWrapperTop = $mapWrapper.offset().top;

    $(window).on('scroll', function(event) {
        if(mapEnabled) return;

        if( $(this).scrollTop() + $(this).height() >= mapWrapperTop ) {
            // lazy (change SID)
            $mapWrapper.append('<script type="text/javascript" charset="utf-8" src="https:\/\/api-maps.yandex.ru\/services\/constructor\/1.0\/js\/?sid=SID&width=100%&height=100%&lang=ru_RU&sourceType=constructor"><\/script>');

            mapEnabled = true;
        }
    });
});