HTML Checking for Large Sites

The <script> tag allows authors to include dynamic scripts and data blocks in their documents. When the src is present, this tag accepts a type attribute which must be either:

• an empty string
• text/javascript (that’s the default, so it can be omitted)
• module

Examples:

<!-- This is valid, without a type it defaults to JavaScript -->
<script src="app.js"></script>

<!-- This is valid, but will warn that it can be omitted -->
<script type="text/javascript" src="app.js"></script>

<!-- An empty attribute is valid, but will warn that it can be omitted -->
<script type="" src="app.js"></script>

<!-- The module keyword is also valid as a type -->
<script type="module" src="app.js"></script>

<!-- Any other type is invalid -->
<script type="wrong" src="app.js"></script>
<script type="text/html" src="app.js"></script>
<script type="image/jpeg" src="app.js"></script>

Learn more:

• HTML Spec: the script element
• MDN: the script element

The <textarea> element does not have a type attribute.

The HTML <textarea> element represents a multi-line plain-text editing control, and is useful when you want to allow users to enter a sizeable amount of free-form text, for example a comment on a review or feedback form.

Learn more:

• HTML Living Spec: textarea
• MDN: textarea

The value rocketlazyloadscript used in a <script> tag is not a valid one according to the HTML specification. It is introduced by the WP Rocket Wordpress extension.

Learn more:

• WP Rocket: W3C Validation errors
• HTML Spec: Script type
• MDN: Script element

The value provided on the type attribute of an a element is not a valid MIME type.

The type attribute expects a MIME type that hints at the linked URL’s format.

Read more:

• MDN: type attribute on a
• MDN: common MIME types

The type attribute on <a> elements, when present, gives a hint on the MIME type of the linked resource, for example:

<a href="application/pdf" src="book.pdf">Read our book</a>
<a href="image/jpeg" src="photo.jpeg">See a photo</a>

That is, we’re talking about the type of the linked resource, not the type of the <a> element, as it’s sometimes misunderstood. The following example is invalid because button is not a valid MIME type.

<a href="/order.php" type="button">Submit</a>

Learn more:

• HTML Spec: the type attribute

The value used to define the type of a link is not valid. You’re probably using a URL instead of a valid type.

Example of a valid type:

<link rel="icon" type="image/png" href="favicon.png">

Read more:

• HTML Spec: link types

input elements can be of different types but zip is not one of the allowed. Consider using a generic type like text instead.

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>

Learn more:

• MDN: JavaScript Modules

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.

Learn more:

• MDN: The script element

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:

* MDN: HTMLScriptElement

A <script> start tag has been found in an unexpected place in the document structure. Check that the <script> section appears within the <head> or <body> sections.

Here’s an example of a script inserted in the head of the document:

<!DOCTYPE html>
<html>
  <head>
    <title>Test</title>
    <script>
      console.log("Hello from the head");
    </script>
  </head>
  <body>
    <p></p>
  </body>
</html>

Learn more:

* MDN: script element

A <script> element has been found that is using the now obsolete charset attribute. You can safely remove this attribute.

For example, this is using both type and charset attributes, with their default values. Both can be removed:

<script src="app.js" type="text/javascript" charset="UTF-8"></script>

and just use this:

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

Learn more:

• HTML Spec: obsolete but conforming features

The <script> tag allows authors to include dynamic scripts and data blocks in their documents. This tag accepts two optional attributes, type (which is unnecessary if it’s JavaScript, as that’s the default), and src to indicate the URL of the external script to use.

The language attribute is now obsolete and should not be used.

Read more about:

• HTML Living Standard: the script element
• W3C: HTML5 obsolete features

The HTML <style> element contains style information for a document, or part of a document, defined in CSS. This element does not need the type attribute anymore, so it should be omitted.

For example, this style defines that <p> elements should be in red color.

<style type="text/css">
p {
  color: red;
}
</style>
<p>This text will be red.</p>

But, the type attribute is not used anymore, so we can just use this:

<style>
p {
  color: red;
}
</style>
<p>This text will be red.</p>

Read more:

MDN: The Style information element WordPress plugin: Type Attribute Warnings Removal

The default type for <script> tags is JavaScript, so you don’t need to include the type for JS resources.