Lazy load images with IntersectionObserver
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if(window.IntersectionObserver){ | |
const observe = function (entries, observer) { | |
entries.forEach(function(entry) { | |
if(entry.isIntersecting) { | |
const img = entry.target | |
const src = img.dataset.src | |
const srcset = img.dataset.srcset | |
requestIdleCallback(function () { | |
if(srcset) { | |
img.srcset = srcset | |
} | |
img.src = src | |
}) | |
observer.unobserve(img) | |
} | |
}) | |
} | |
const observer = new IntersectionObserver(observe, {}) | |
const images = document.querySelectorAll('img.lazy') | |
images.forEach(function(img) { | |
observer.observe(img) | |
}) | |
} | |
else { | |
const images = document.querySelectorAll('img.lazy') | |
for(let i=0 ; i < images.length; i++){ | |
const img = images[i] | |
const src = img.dataset.src | |
const srcset = img.dataset.srcset | |
if(srcset) { | |
img.srcset = srcset | |
} | |
img.src = src | |
} | |
} |
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