A BrowserSetting object whose underlying value is a string.

Firefox enables the user to set their own colors for document backgrounds and text. By default these values are only applied when a high-contrast theme is selected (a high-contrast theme is a feature of some operating system UIs that increases the contrast for improved accessibility). However, users can also choose to apply these colors always or never. This browser setting exposes that preference.

Its underlying value is a string that may take any one of the following values:

  • "high-contrast-only": Apply the user's choices only when a high-contrast theme is selected. This is the default.
  • "never":  Never apply the user's choices.
  • "always": Always apply the user's choices.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxOperaSafariFirefox for Android
openUrlbarResultsInNewTabsChrome No support NoEdge No support NoFirefox Full support 61Opera No support NoSafari No support NoFirefox Android Full support 61


Full support  
Full support
No support  
No support


Set the setting to "always":

function logResult(result) {
  console.log(`Setting was modified: ${result}`);

browser.browserSettings.overrideDocumentColors.set({value: "always"}).