HTML Guide
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/javascriptLearn more:
Related W3C validator issues
The combination of type="module" and defer is not allowed. The type="module" attribute itself implies that the script should be executed in a deferred way, hence using the defer attribute is unnecessary and invalid.
Steps to Fix the Issue:
- Remove the defer Attribute: When you use type="module", you should not include the defer attribute since module scripts defer automatically.
Incorrect Code:
<script type="module" defer src="example.js"></script>Corrected Code:
<script type="module" src="example.js"></script>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>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.
The default type for <script> tags is JavaScript, so you don’t need to include the type for JS resources.
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.
The type dob is not valid for an input. If you want to build a date picker field, you can use the native HTML input elements with type date, datetime-local, or a generic text input decorated with JavaScript and CSS.
In HTML, the type attribute for the <input> element specifies the type of input control that is to be displayed. The type attribute can have values like text, password, email, date, etc. Using an unsupported or invalid value like dob (which presumably stands for “date of birth”) will cause this validation error.
Here’s an example of how you can correct this issue by using a supported type attribute value for the date of birth input:
<label for="dob">Date of Birth:</label>
<input type="date" id="dob" name="dob">In this corrected example, we’ve used the type="date" attribute value for the date of birth input. This is a valid type for handling dates in HTML forms. Replace the input type with a supported type according to the specific data you need to capture.
Alternatively you can use a JavaScript library to build a date picker on a generic text input. For example, the popular bootstrap-datepicker library will generate a date picker around a text input.
Ensure the src attribute on the script element is non-empty and points to a valid resource.
The src attribute in a script element specifies the URL of an external script file. An empty src attribute is invalid because it tells the browser to fetch a resource from a URL that is not provided, leading to loading errors. Instead, ensure that the src attribute contains a valid file path or URL to an existing script file. If the script content is meant to be inline, you should omit the src attribute altogether and include the script content directly within the script element.
Example of a Valid External Script
Here is a valid example of a script element with a non-empty src attribute:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Valid Script Example</title>
</head>
<body>
<script src="path/to/script.js"></script>
</body>
</html>Example of a Valid Inline Script
If the script is to be written inline, exclude the src attribute and write the JavaScript code directly within the script tags:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Inline Script Example</title>
</head>
<body>
<script>
console.log('This is an inline script.');
</script>
</body>
</html>Troubleshooting
Double-check the script’s file path:
- Ensure the file path you provide in the src is correct relative to the HTML file.
- Make sure the script file exists in the location specified.
- If using a network URL, verify that the URL is correct and accessible.
Empty type attributes are invalid on the <a> element; you must either remove the type attribute or provide a valid MIME type value.
The type attribute on an <a> (anchor) element specifies the MIME type of the linked resource. According to the WHATWG HTML specification and W3C validator, the value of the type attribute cannot be an empty string. It should be a valid MIME type, such as application/pdf or text/html. If you do not know the MIME type or it’s not relevant, you should omit the attribute.
Incorrect HTML example (causes validation error):
<a href="document.pdf" type="">Download PDF</a>Correct HTML example (remove the invalid attribute):
<a href="document.pdf">Download PDF</a>Correct HTML example (provide a valid MIME type):
<a href="document.pdf" type="application/pdf">Download PDF</a>If the type is unknown or unnecessary, leaving it out is preferred to using an empty value.
The input element does not support a type attribute value of numeric; the correct attribute value is number.
HTML input elements have a type attribute that specifies the kind of data that the input is expected to contain. When creating a form field for numeric input, you should use type="number", which provides an input control with features like increment/decrement controls, depending on the browser. This allows browsers to render the appropriate interface for numeric inputs and also provides built-in client-side validation to ensure that the entered data is a numerical value.
Here’s an example of how to correctly define an input for numeric values:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Number Input Example</title>
</head>
<body>
<form>
<label for="quantity">Quantity:</label>
<input type="number" id="quantity" name="quantity" min="1" max="10">
<input type="submit" value="Submit">
</form>
</body>
</html>In this example, the input element has a type of number, allowing users to input or select a numeric value within the specified range of 1 to 10. Using type="number" instead of any incorrect value, like numeric, ensures that your HTML is compliant with W3C standards.
The async attribute is boolean: the presence of a boolean attribute on an element represents the true value, and the absence of the attribute represents the false value. As a boolean attribute, it does not need to be passed any value such as true or 1 to activate the async property.
For classic scripts, if the async attribute is present, then the classic script will be fetched in parallel to parsing and evaluated as soon as it is available.
For module scripts, if the async attribute is present then the scripts and all their dependencies will be executed in the defer queue, therefore they will get fetched in parallel to parsing and evaluated as soon as they are available.
<script async src="app.js"></script>
<script async type="module">
/* JavaScript module code here */
</script>