Wednesday, August 14, 2019

Lazy Loading Images and Iframes with the Google Chrome Browser

Lazy loading is a term that describes delaying the loading of  below-the-fold images until the web page visitor scrolls down the page to them. The major benefits are quicker load times, less bandwidth, and reduced memory usage. Until this announcement by Chrome, developers needed Javascript event handlers create this effect.

The latest version of Chrome browser (Chrome 76) will support native lazy loading, by implementing the new HTML loading attribute for img and iframe elements. 
Values for the loading attribute are:
  • auto (default browser loading)
  • lazy (defer loading the resource until it reaches a calculated distance from the viewport)
  • eager  (load the resource immediately)
Here’s an HTML example of adding lazing loading to the img element:
HTML img ellement with loading="lazy" attribute
HTML img element with the loading attribute
Although not yet part of an official W3C HTML5 Recommendation, the loading attribute is in the process of being added to the HTML5 standard and is documented at Keep in mind that at this time only the Chrome browser supports native lazy loading and other browsers will ignore the loading attribute.