Lazy Load Remastered

Lazy Load delays loading of images in long web pages. Images outside of viewport will not be loaded before user scrolls to them. This is opposite of image preloading.

This is a modern vanilla JavaScript version of the original Lazy Load plugin. It uses Intersection Observer API to observe when the image enters the browsers viewport. Original code was inspired by YUI ImageLoader utility by Matt Mlinac. New version loans heavily from a blog post by Dean Hume.

Basic Usage

By default Lazy Load assumes the URL of the original high resolution image can be found in data-src attribute. You can also include an optional low resolution placeholder in the src attribute.

``html




`

With the HTML in place you can then initialize the plugin using the factory method. If you do not pass any settings or image elements it will lazyload all images with class lazyload.

`js
lazyload();
`

If you prefer you can explicitly pass the image elements to the factory. Use this for example if you use different class name.

`js
let images = document.querySelectorAll(".branwdo");
lazyload(images);
`

If you prefer you can also use the plain old constructor.

`js
let images = document.querySelectorAll(".branwdo");
new LazyLoad(images);
`

The core IntersectionObserver can be configured by passing an additional argument

`js
new LazyLoad(images, {
root: null,
rootMargin: "0px",
threshold: 0
});
`

Additional API

To use the additional API you need to assign the plugin instance to a variable.

`js
let lazy = lazyload();
`

To force loading of all images use loadimages().

`js
lazy->loadImages();
`

To destroy the plugin and stop lazyloading use destroy().

`js
lazy->destroy();
`

Note that destroy() does not load the out of viewport images. If you also
want to load the images use loadAndDestroy().

`js
lazy->loadAndDestroy();
`

Additional API is not avalaible with the jQuery wrapper.

jQuery Wrapper

If you use jQuery there is a wrapper which you can use with the familiar old syntax. Note that to provide BC it uses data-original by default. This should be a drop in replacement for the previous version of the plugin.

`html


`

`js
$("img.lazyload").lazyload();
`

Cookbook

$3

Low resolution placeholder ie. the "blur up" technique. You can see this in action in this blog entry. Scroll down to see blur up images.

`html
src="thumbnail.jpg"
data-src="original.jpg"
width="1024" height="768" />
`

`html