The imageSrcset property of the HTMLLinkElement interface is a string which identifies one or more comma-separated image candidate strings. This property reflects the value of the <link> element's imagesrcset attribute. This property can retrieved or set the imagesrcset attribute value.
Each image candidate string contains an image URL and an optional width and/or pixel density descriptor indicating the conditions under which that candidate image should be used.
"images/team-photo.jpg, images/team-photo-retina.jpg 2x, images/team-photo-large.jpg 1400w"
For HTML <link> elements with rel="preload" and as="image" set, the imagesrcset attribute has similar syntax and semantics as the <img> element's srcset attribute, which indicates to preload the appropriate resource used by an <img> element with corresponding values for its srcset and sizes attributes.
If the imageSrcset property includes width descriptors, the imageSizes property must be non-null, or the imageSrcset value will be ignored.
A string composed of a comma-separated list of one or more image candidate strings, or the empty string "" if unspecified..
Given the following <link> element:
<link
rel="preload"
as="image"
imagesizes="50vw"
imagesrcset="bg-narrow.png, bg-wide.png 800w" />…we can access the imagesrcset attribute value, and update it, using the imageSrcset property:
const link = document.querySelector("link");
log(`Original: ${link.imageSrcset}`);
// add an image candidate string
link.imageSrcset += ", bg-huge.png 1200w";
log(`Updated: ${link.imageSrcset}`);