The lazyload policy grants the ability for a document to control whether assets are loaded lazily, ie. only when the user scrolls the docuement such that the asset is within the visible area of the viewport.

If the policy is enabled, or not specified, the document has full control over lazy-loading, using the lazyload attribute of <img> and <iframe> tags. If the policy is disabled, the user agent will lazy-load all assets regardless of the presence or value of any lazyload attribute on the element itself.

How to apply this policy

Send the following HTTP header to control the lazyload policy, and disallow it on all origins:

Feature-Policy: lazyload 'none'

Does it work?

Currently Firefox, and Chromium based browsers, such as Google Chrome, Samsung Internet, and Opera, are the only user-agents to support Feature Policy. The minimum version that correctly recognises the lazyload policy is:

Mozilla Firefox


Google Chrome

Not supported

Microsoft Edge

Not supported

Apple Safari

Not supported