Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
HTML issues tagged as as.
<link> element that is using the
preload value in the
rel attribute is missing the
as attribute, used to indicate the type of the resource.
preload value of the
rel attribute lets you declare fetch requests in the HTML’s
<head>, specifying resources that your page will need very soon, which you want to start loading early in the page lifecycle, before browsers’ main rendering machinery kicks in. This ensures they are available earlier and are less likely to block the page’s render, improving performance.
as attribute specifies the type of content being loaded by the
<link>, which is necessary for request matching, application of correct content security policy, and setting of correct
Accept request header.
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