Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
HTML issues tagged as “imagesrcset”.
For rel="preload" and as="image" only, the imagesrcset attribute is a sourceset attribute that indicates to preload the appropriate resource used by an img element with corresponding values for its srcset and sizes attributes.
6,250 HTML checks per week. Fully automated.
Save time using our automated web checker. Let our crawler check your web pages on the W3C Validator.