Validación HTML: Bad value “Content-Style-Type” for attribute “http-equiv” on element “meta”.

Acerca de este problema HTML

Why This Is an Issue

In HTML 4 and XHTML, the Content-Style-Type HTTP header (and its <meta http-equiv> equivalent) told the browser which stylesheet language to use when interpreting inline style attributes and <style> elements. This was theoretically necessary because the specification allowed for alternative stylesheet languages beyond CSS.

In practice, CSS became the only stylesheet language browsers support. The HTML living standard (maintained by WHATWG) recognizes this reality and defines a strict list of valid http-equiv values. Content-Style-Type is not among them. The only valid values include content-type, default-style, refresh, x-ua-compatible, content-security-policy, and a few others defined in the spec.

Because every browser defaults to CSS for all styling, this meta tag serves no functional purpose. Keeping it in your markup only produces a validation error and adds unnecessary bytes to your document.

Similarly, the related Content-Script-Type meta tag (which declared the default scripting language) is also obsolete for the same reasons — JavaScript is the universal default.

How to Fix It

The fix is straightforward: remove the <meta http-equiv="Content-Style-Type" ...> tag from your document’s <head>. No replacement is needed. Browsers will interpret all stylesheets as CSS and all scripts as JavaScript without any explicit declaration.

If you inherited this tag from a legacy template or an older CMS, you can safely delete it with no impact on your site’s appearance or behavior.

Examples

❌ Invalid: Using the obsolete `Content-Style-Type` pragma

<head>
  <meta charset="utf-8">
  <meta http-equiv="Content-Style-Type" content="text/css">
  <title>My Page</title>
</head>

This triggers the validator error: Bad value “Content-Style-Type” for attribute “http-equiv” on element “meta”.

✅ Valid: Simply remove the obsolete meta tag

<head>
  <meta charset="utf-8">
  <title>My Page</title>
</head>

No replacement is needed. CSS is already the default stylesheet language in all browsers.

❌ Invalid: Both `Content-Style-Type` and `Content-Script-Type` (common in legacy templates)

<head>
  <meta charset="utf-8">
  <meta http-equiv="Content-Style-Type" content="text/css">
  <meta http-equiv="Content-Script-Type" content="text/javascript">
  <title>Legacy Page</title>
</head>

✅ Valid: Remove both obsolete declarations

<head>
  <meta charset="utf-8">
  <title>Legacy Page</title>
</head>

Both Content-Style-Type and Content-Script-Type are obsolete. Removing them has zero effect on how browsers render your page, and your HTML will pass validation cleanly.