HTML Checking for Large Sites
Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
HTML issues tagged as defer.
The defer and async boolean attributes of the <script> element control how an external script should be executed once it has been downloaded. These attributes only make sense when referring to external scripts, so a src attribute must also be present to specify the location of the script.
Example:
<script defer src="app.js"></script>
If your script is not external, and is inlined within the HTML document, then you should remove the defer attribute, like in this example:
<script>
console.log("hello");
</script>
Learn more:
When was the last time you validated your whole site?
Keep your sites healthy checking for A11Y/HTML issues on an automated schedule.