fosc.space/js/main.js

function loadMap() {
    var site = "https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d1580.5054989176758!2d-0.9796837724532329!3d37.60190018337746!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0xd6341863c83cf8f%3A0xe24278be476b56b8!2sFOSC!5e0!3m2!1ses!2ses!4v1544058887076";
    document.getElementById('map').src = site;
}

document.addEventListener("DOMContentLoaded", function() {
  var lazyloadImages;    

  if ("IntersectionObserver" in window) {
    lazyloadImages = document.querySelectorAll(".lazy");
    var imageObserver = new IntersectionObserver(function(entries, observer) {
      entries.forEach(function(entry) {
        if (entry.isIntersecting) {
          var image = entry.target;
          image.src = image.dataset.src;
          image.classList.remove("lazy");
          imageObserver.unobserve(image);
        }
      });
    });

    lazyloadImages.forEach(function(image) {
      imageObserver.observe(image);
    });
  } else {  
    var lazyloadThrottleTimeout;
    lazyloadImages = document.querySelectorAll(".lazy");
    
    function lazyload () {
      if(lazyloadThrottleTimeout) {
        clearTimeout(lazyloadThrottleTimeout);
      }    

      lazyloadThrottleTimeout = setTimeout(function() {
        var scrollTop = window.pageYOffset;
        lazyloadImages.forEach(function(img) {
            if(img.offsetTop < (window.innerHeight + scrollTop)) {
              img.src = img.dataset.src;
              img.classList.remove('lazy');
            }
        });
        if(lazyloadImages.length == 0) { 
          document.removeEventListener("scroll", lazyload);
          window.removeEventListener("resize", lazyload);
          window.removeEventListener("orientationChange", lazyload);
        }
      }, 20);
    }

    document.addEventListener("scroll", lazyload);
    window.addEventListener("resize", lazyload);
    window.addEventListener("orientationChange", lazyload);
  }
})