Created
May 23, 2019 15:16
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Lazy load images :)
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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; | |
} | |
}); | |
} |
P.S. this uses var
for ie11, but you can use let
if you have babel recompile the code
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This looks for images with the class of lazy and that have
data-src
attributes set for their urls. When they are visible to the user thedata-src
gets put in thesrc
attribute. also works withdata-srcset