AI solution for Interview Question on BFE.dev
71. How to implement lazy load for images?

Before the native lazy-load, one way to implement lazy-loading for images is to use a JavaScript library or plugin. One popular library is LazyLoad which uses data attributes to determine which images to load only when they come into view.

The basic steps to implement lazy-load using LazyLoad library are:

1. Add the LazyLoad JavaScript file to your project.
2. Add a data-src attribute to your images with the URL to the image to be loaded.
3. Change the src attribute to a placeholder image, such as a transparent 1x1 pixel.
4. Initialize the LazyLoad library on page load or when the images are added to the DOM.
5. The library will automatically replace the placeholder image with the actual image when it comes into view.

Here's an example of how to use LazyLoad library:

<img data-src="image.jpg" src="placeholder.gif" class="lazyload" />
<script src="lazyload.min.js"></script>
<script>
  var lazyLoadInstance = new LazyLoad({
    elements_selector: ".lazyload"
  });
</script>

In the above example, the "lazyload" class is added to the image tag to indicate which images should be lazy-loaded. Once the library is initialized, any images on the page with the lazyload class will be loaded only when they come into view.