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Bad value X for attribute “type” on element “script”: Subtype missing.
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
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Related W3C validator issues
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>
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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.
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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.
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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.
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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>
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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">
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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>
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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.
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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>
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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>
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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:
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:
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.
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