init

2019-05-23 11:26:46 -04:00
commit d51f3ae0d0
4 changed files with 52 additions and 0 deletions
--- a/Readme.md
+++ b/Readme.md
@@ -0,0 +1,3 @@
+## Lazy loading images
+
+A simple example of lazy loading images
--- a/car.png
+++ b/car.png
--- a/index.html
+++ b/index.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta http-equiv="X-UA-Compatible" content="ie=edge">
+    <title>HI</title>
+</head>
+<body>
+    <H1>Image</H1>
+    <img data-src="car.png" class="lazy" />
+    <script src="lazyLoad.js"></script>
+</body>
+</html>
--- a/lazyLoad.js
+++ b/lazyLoad.js
@@ -0,0 +1,35 @@
+if(window.IntersectionObserver) {
+    document.addEventListener("DOMContentLoaded", function() {
+    var lazyImages = [].slice.call(document.querySelectorAll(".lazy"));
+      var lazyImageObserver = new IntersectionObserver(function(entries, observer) {
+        entries.forEach(function(entry) {
+          if (entry.isIntersecting) {
+            var lazyImage = entry.target;
+            if(lazyImage.dataset.src) {
+              lazyImage.src = lazyImage.dataset.src;
+            }
+            if(lazyImage.dataset.srcset) {
+              lazyImage.srcset = lazyImage.dataset.srcset;
+            }
+
+            lazyImage.classList.remove("lazy");
+            lazyImageObserver.unobserve(lazyImage);
+          }
+        });
+      });
+
+      lazyImages.forEach(function(lazyImage) {
+        lazyImageObserver.observe(lazyImage);
+      });
+  });
+} else {
+      var lazyImages = [].slice.call(document.querySelectorAll(".lazy"));
+      lazyImages.forEach(function(image) {
+          if(image.dataset.srcset) {
+            image.srcset = image.dataset.srcset;
+          }
+          if(image.dataset.src) {
+            image.src = image.dataset.src;
+          }
+      });
+}