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

The specified type for an script element is not a valid MIME type as it’s missing a subtype.

A MIME type most-commonly consists of just two parts: a type and a subtype, separated by a slash (/) — with no whitespace between, for example:

text/javascript

Learn more:

• MDN: Structure of a MIME type
• HTML Spec: the script element
• MDN: the script element

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

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.