Lazy Load Plugin

Smart4y Lazy Load is a plugin that helps optimize the content in posts or pages of your site – for their faster loading. Plugin is written in pure Javascript without any Javascript library dependencies – fast and lightweight. Optimization is based on the principle of lazy handling, which loads content as needed (mostly pictures). It also offers SEO optimization for images.


  • Type of content: You can specify where will be used lazy loading – in posts, pages, for post thumbnails and so on.
  • Treshold: Possibility to define value for earlier load of images and iframes.
  • Lazy load: Support for lazy load of images or iframes.
  • SEO: Adds the missing alt attribute or posiibility override existing alt attributes.
  • Ajax: No need to initialize the plugin after each ajax call.
  • Indexing: Indexing content by robots is not a problem.

Lazy loading

Lazy loading means loading images or iframes on websites asynchronously — mostly conditionally, only when they appear in the browser’s viewport. This means that if users don’t scroll all the way down, images or iframes placed at the bottom of the page won’t even be loaded. Benefits are:

  • Speed up your site.
  • Decreases the number of HTTP requests during the first page load.
  • The size of downloaded data will be reduced (mostly important for mobile devices).

Responsive images

Keeping the aspect ratio of images is no problem. Plugin prevents page content jumping during scrolling of page or when using anchor navigation – feature requires defined image width and height.

aspect ratio

Indexing of images

Lazy loading is applied only for real user visitors. Original content is served to robots (like Googlebot) that index your site – images that are located below the fold does not have to be loaded on the page until they are in the viewable portion of the screen.


Plugin automatically adds the missing alt attribute to the corresponding filename of the image. For example: filename “my-image_150x150.jpg” is transform to “my image“.

Ajax support

Plugin allows two modes:

  • Automatic mode: Automatically check lazy elements after AJAX call. Works only in modern browsers.
  • Manual mode: After every ajax page update you must check lazy elements using Smart4y Lazy Load API.


Example includes: SEO – adds the missing alt attributes, treshold: 0 px, aspect ratio: prevents page content jumping during scrolling of page (try navigate to last image using an anchor).

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Browser support

android andorid browser 4+, chrome chrome, firefox firefox, ie ie10+, edge, opera opera, safari safari



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