Bad value X for attribute “http-equiv” on element “meta”.

The http-equiv attribute contains a misspelled or invalid value.

The http-equiv attribute on the <meta> element acts as a pragma directive, simulating an HTTP response header. The HTML specification only allows a specific set of values for this attribute. The valid values include content-type, default-style, refresh, X-UA-Compatible, and content-security-policy.

The value X-UA-Compatible was historically used to tell Internet Explorer to use a specific rendering engine. While it's largely obsolete now that IE is no longer supported, the HTML spec still recognizes it as a valid value.

Common mistakes that trigger this error include:

• Typos like X-UA-Complatible, X-UA-Compatable, or X-UA-Compatble
• Using non-standard values like imagetoolbar, cleartype, or cache-control
• Using values that were valid in older HTML versions but are no longer recognized

HTML Examples

❌ Invalid: misspelled value

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

✅ Valid: correctly spelled value

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

Note that the chrome=1 portion referenced Google Chrome Frame, a discontinued plugin. It's safe to remove it along with the entire <meta> tag if you no longer need to support Internet Explorer.

Learn more:

MDN Reference

MDN: meta element

→

WHATWG Spec

WHATWG HTML Standard: Semantics

→

MDN Reference

MDN: http-equiv attribute

→