We're looking for a user researcher to understand the needs of developers and designers. Is this you or someone you know? Check out the post: https://mzl.la/2IGzdXS

Indicates whether the document is rendered in Quirks mode or Standards mode.

Syntax

mode = document.compatMode 

Values

  • "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.
mode
Is an enumerated value that can be:

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

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes ? Yes ? ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes ? Yes ? ? ?

Document Tags and Contributors

Last updated by: fscholz,