# A “meta” element with an “http-equiv” attribute whose value is “X-UA-Compatible” must have a “content” attribute with the value “IE=edge”.
> Canonical HTML version: https://rocketvalidator.com/html-validation/a-meta-element-with-an-http-equiv-attribute-whose-value-is-x-ua-compatible-must-have-a-content-attribute-with-the-value-ie-edge
> Attribution: Rocket Validator (https://rocketvalidator.com)
> License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
The `X-UA-Compatible` meta tag was originally introduced to control which rendering engine Internet Explorer would use to display a page. Developers could force IE to emulate older versions (e.g., `IE=7`, `IE=9`) or use the latest available engine with `IE=edge`. The value `IE=edge,chrome=1` was also commonly used to activate the Google Chrome Frame plugin, which allowed Internet Explorer to use Chrome's rendering engine instead.
The HTML specification now only permits the value `IE=edge` for this meta tag. Other values are considered invalid for several reasons:
- **Google Chrome Frame is discontinued.** The `chrome=1` directive targeted a plugin that was retired in February 2014 and is no longer supported by any browser.
- **Legacy IE rendering modes are obsolete.** Internet Explorer itself has been retired, making emulation modes like `IE=EmulateIE7` or `IE=9` pointless.
- **Standards compliance.** The WHATWG HTML living standard explicitly requires the `content` attribute value to be `IE=edge` when `http-equiv="X-UA-Compatible"` is used.
In practice, since all modern browsers use their latest rendering engine by default, this meta tag has little functional impact today. If your site no longer needs to support Internet Explorer at all, you can safely remove the tag entirely. If you choose to keep it — for example, in environments where legacy IE browsers might still access your site — ensure the value is exactly `IE=edge`.
## Examples
### Invalid: Using `chrome=1` with `IE=edge`
This was a common pattern when Google Chrome Frame was active, but it now triggers a validation error:
```html
```
### Invalid: Using a legacy IE rendering mode
Forcing a specific IE version is no longer valid:
```html
```
### Invalid: Specifying a particular IE version
```html
```
### Valid: Using `IE=edge`
The only accepted value is `IE=edge`:
```html
```
### Valid: Removing the tag entirely
If you don't need Internet Explorer compatibility, the simplest fix is to remove the meta tag altogether. A minimal valid document without it:
```html
My Page
Hello, world!
```