HTMLImageElement: loading property

The loading property of the HTMLImageElement interface provides a hint to the browser on how to handle the loading of the image which is currently outside the window’s visual viewport. This helps to optimize the loading of the document’s contents by postponing loading the image until it’s expected to be needed, rather than immediately during the initial page load. It reflects the <img> element’s loading content attribute.

Value

A string whose value is one of eager or lazy. For their meanings, see the HTML <img> reference.

Examples

Basic usage

The addImageToList() function shown below adds a photo thumbnail to a list of items, using lazy-loading to avoid loading the image from the network until it’s actually needed.

function addImageToList(url) {
  const list = document.querySelector("div.photo-list");

  const newItem = document.createElement("div");
  newItem.className = "photo-item";

  const newImg = document.createElement("img");
  newImg.loading = "lazy";
  newImg.width = 320;
  newImg.height = 240;
  newImg.src = url;

  newItem.appendChild(newImg);
  list.appendChild(newItem);
}

Specifications

Browser compatibility

See also

• The <img> element
• Web performance in the MDN Learning Area
• Lazy loading in the MDN web performance guide