link as only allowed with rel=preload or rel=modulepreload Web Standard


A link element with an as attribute must have a rel attribute that contains the value preload or the value modulepreload.

Applicable standards

Change history

  • 6.38 No longer allows rel=prefetch with as.
  • 5.38 Jul 2020 Now allows rel=prefetch with as.
  • 5.37 May 2020 Now detects when required as is missing.
  • 5.25 Apr 2017 Added to W3 validator in March 2017.

This page describes a web site issue detected in HTML documents by SortSite Desktop and OnDemand Suite.

Rule ID: W3cHtml5LinkPreloadAs