details

An object with the following properties:

color

The color, specified as one of:

• a string: any CSS <color> value, for example "red", "#FF0000", or "rgb(255,0,0)". If the string is not a valid color, the returned promise will be rejected and the text color won't be altered.
• a browserAction.ColorArray object.
• null. If a tabId is specified, it removes the tab-specific badge text color so that the tab inherits the global badge text color. Otherwise it reverts the global badge text color to the default value.

tabId Optional

integer. Sets the badge text color only for the given tab. The color is reset when the user navigates this tab to a new page.

windowId Optional

integer. Sets the badge text color only for the given tab.

• If windowId and tabId are both supplied, the function fails and the color is not set.
• If windowId and tabId are both omitted, the global badge text color is set instead.

A badge text color that starts off as red, and turns green when the browser action is clicked:

browser.browserAction.setBadgeText({ text: "1234" });
browser.browserAction.setBadgeTextColor({ color: "red" });

browser.browserAction.onClicked.addListener(() => {
  browser.browserAction.setBadgeTextColor({ color: "green" });
});

Set the badge text color only for the active tab:

browser.browserAction.setBadgeText({ text: "1234" });
browser.browserAction.setBadgeTextColor({ color: "red" });

browser.browserAction.onClicked.addListener((tab) => {
  browser.browserAction.setBadgeTextColor({
    color: "green",
    tabId: tab.id,
  });
});