Document.compatMode
The Document.compatMode read-only property indicates whether the document is rendered in Quirks mode or Standards mode.
Syntax
const mode = document.compatMode
Value
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 standardized, 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
| Specification |
|---|
| DOM Standard (DOM) # ref-for-dom-document-compatmode① |
Browser compatibility
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
compatMode |
1 |
12 |
1 |
6 |
≤12.1 |
3.1 |
1 |
18 |
4 |
≤12.1 |
2 |
1.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/Document/compatMode