Indicates whether the document is rendered in Quirks mode or Standards mode.
Syntax
mode = document.compatMode;
Values
mode- Is an enumerated value that can be:
"BackCompat"if the document is in quirks mode."CSS1Compat"if the document is in no-quirks (also known as "standards") mode or limited-quirks (also known as "almost standards") mode.
Note: all these modes are now defined in standards, so the older "standards" and "almost standards" names are nonsensical and no longer used in standards.
Example
if (document.compatMode == "BackCompat") {
// in Quirks mode
}
Specifications
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | Yes | ? | Yes | ? | ? | ? |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | Yes | Yes | ? | Yes | ? | ? | ? |