HTML Validation

Bad value “”Content-Security-Policy”” for attribute “http-equiv” on element “meta”.

About This HTML Issue

The W3C HTML Validator issue you’re encountering indicates that the value specified for the http-equiv attribute in a <meta> tag is not valid. This often happens due to incorrect formatting, spelling errors, or extraneous characters in the attribute value.

To resolve this issue, ensure that the http-equiv attribute is spelled correctly and that it contains valid values. For a basic Content Security Policy (CSP), the correct way to specify it in the <meta> tag is as follows:

Correct Usage of `<meta>` with `http-equiv`

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="Content-Security-Policy" content="default-src 'self';">
    <title>Document Example</title>
</head>
<body>
    <h1>Hello, World!</h1>
</body>
</html>

Fixes to Apply:

Ensure Correct Spelling: The attribute value must be spelled exactly as “Content-Security-Policy” (case-sensitive).
Check for Extraneous Characters: Make sure there are no extra quotes or spaces within the attribute value.

Example of a Bad Value:

If your original <meta> tag looks something like this:

<meta http-equiv=""Content-Security-Policy"" content="default-src 'self';">

You should change it to:

<meta http-equiv="Content-Security-Policy" content="default-src 'self';">

Learn more:

→ MDN: content-security-police

Last reviewed: August 01, 2024

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Related W3C Validator Issues

Element “meta” is missing one or more of the following attributes: “charset”, “content”, “http-equiv”, “itemprop”, “name”, “property”.

There’s an incomplete or incorrectly formed <meta> tag. The <meta> tag in HTML is used to provide metadata about the HTML document. This metadata is typically specified using attributes like charset, content, http-equiv, itemprop, name, and property.

To fix this issue, you need to ensure that your <meta> tags include at least one of these attributes. Here are some examples of properly formed <meta> tags with each of these attributes:

Using the charset attribute:
```
<meta charset="UTF-8">
```
This specifies the character encoding for the HTML document, which is crucial for displaying text correctly in different languages.
Using the content and name attributes:
```
<meta name="description" content="A brief description of the webpage content.">
```
This provides a description of the webpage content, which can be used by search engines.
Using the http-equiv and content attributes:
```
<meta http-equiv="refresh" content="30">
```
This specifies information to be passed to the browser, such as refreshing the page every 30 seconds.
Using the property and content attributes:
```
<meta property="og:title" content="Your Webpage Title">
```
This is used for Open Graph meta tags, which improve the appearance of shared content on social media platforms.

Correct Usage Example

Here’s an example of an HTML document with a properly formed set of <meta> tags:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="A brief description of the webpage content.">
    <meta http-equiv="refresh" content="30">
    <meta property="og:title" content="Your Webpage Title">
    <title>Document</title>
</head>
<body>
<!-- Page content goes here -->

</body>
</html>

A document must not include both a “meta” element with an “http-equiv” attribute whose value is “content-type”, and a “meta” element with a “charset” attribute.

In order to define the charset encoding of an HTML document, both of these options are valid, but only one of them must appear in the document:

<!-- This is the preferred way -->

<meta charset="UTF-8">

<!-- This is the older way, also valid -->

<meta http-equiv="content-type" content="text/html; charset=UTF-8">

A “meta” element with an “http-equiv” attribute whose value is “X-UA-Compatible” must have a “content” attribute with the value “IE=edge”.

The only value admitted for the attribute content in a <meta http-equiv="X-UA-Compatible"> is currently IE=edge. You’re probably seeing this issue because the page being validated includes the following meta tag:

<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />

As the Google Chrome Frame plugin was discontinued on February 25, 2014, this is longer supported so you should change that meta tag to:

<meta http-equiv="X-UA-Compatible" content="IE=edge" />

According to this article in Wikipedia:

Google Chrome Frame was a plug-in designed for Internet Explorer based on the open-source Chromium project, first announced on September 22, 2009. It went stable in September 2010, on the first birthday of the project. It was discontinued on February 25, 2014 and is no longer supported.

The plug-in worked with Internet Explorer 6, 7, 8 and 9. It allowed suitably coded web pages to be displayed in Internet Explorer by Google Chrome’s versions of the WebKit layout engine and V8 JavaScript engine.

Bad value “text/html; charset=windows-1251” for attribute “content” on element “meta”: “charset=” must be followed by “utf-8”.

A <meta> tag has been found in the document stating that the charset is windows-1251, but it actually is utf-8. You should update the tag to reflect the actual encoding of the document, for example:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

Bad value “text/html; charset=windows-1252” for attribute “content” on element “meta”: “charset=” must be followed by “utf-8”.

A <meta> tag has been found in the document stating that the charset is windows-1252, but it actually is utf-8. You should update the tag to reflect the actual encoding of the document, for example:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

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