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Meta tags

X-UA-Compatible

A legacy Internet Explorer pragma whose only conforming value is IE=edge. Current user agents must ignore it, so new pages should omit it.

Code examples

Good example
<meta http-equiv="X-UA-Compatible" content="IE=edge">
The only value allowed by the HTML standard, kept here for reading legacy markup. Current browsers ignore it.
Avoid this example
<meta http-equiv="X-UA-Compatible" content="IE=8">
Version-specific Internet Explorer document modes are non-conforming.
Avoid this example
<meta http-equiv="X-UA-Compatible" content="">
An empty pragma has no effect. Omit the element instead.

Recommendations

  • 01
    Remove It From New Pages
    Modern Edge, Chrome, Firefox, and Safari do not use Internet Explorer document modes. The tag adds no value for them.
  • 02
    Use the HTML Doctype
    Start documents with <!doctype html> so browsers use standards mode. That remains relevant; X-UA-Compatible does not.

Related documentation

Related meta tags

Content-Security-Policy

http-equiv

Enforces a Content Security Policy from the document head. A policy limits where scripts, styles, images, connections, and other resources can come from, which reduces the impact of content injection bugs.

<meta http-equiv="Content-Security-Policy" content="default-src 'self'; object-src 'none'; base-uri 'self';">
Uses the same origin by default, blocks plugin content, and limits base URLs to the same origin.

content-type

http-equiv

Provides the legacy pragma form of an HTML character encoding declaration. For conforming HTML, its content must be text/html; charset=utf-8.

<meta http-equiv="content-type" content="text/html; charset=UTF-8">
The only conforming content value for this pragma in an HTML document.

default-style

http-equiv

Selects the preferred CSS style sheet set by name when a page offers alternate titled stylesheets. Browser support is limited.

<meta http-equiv="default-style" content="Main Style">
Valid when a linked stylesheet set has the exact title Main Style.

refresh

http-equiv

Reloads the current page after a delay or performs a timed redirect. Automatic navigation can confuse users, so a server redirect is usually a better choice.

<meta http-equiv="refresh" content="5; URL=https://example.com/next">
Valid timed redirect syntax. Prefer an HTTP redirect unless the visible delay serves a real purpose.

X-UA-Compatible

http-equiv

A legacy Internet Explorer pragma whose only conforming value is IE=edge. Current user agents must ignore it, so new pages should omit it.

<meta http-equiv="X-UA-Compatible" content="IE=edge">
The only value allowed by the HTML standard, kept here for reading legacy markup. Current browsers ignore it.