HTML Checking for Large Sites

<img> tags used to display images require the attribute src to indicate the source of the image, for example <img src="/img/photo.jpg" />.

The async and defer boolean attributes of the <script> element control how an external script should be executed once it has been downloaded. The async attribute makes sense when an external script (defined with the src attribute) is loaded, or when defining a script of type module:

<script async src="app.js"></script>

<script type="module">
  /* JavaScript module code here */
</script>

The charset attribute on a <script> element can be used to specify the character encoding of an external script, whose URL should be specified on the src attribute.

If the script is not external, then the charset attribute should not be used, as the character encoding of the HTML document will be used.

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>