commands

The commands key is an object, and each shortcut is a property of it. The property's name is the name of the shortcut.

Each shortcut's value is an object, with up to 2 properties:

1. suggested_key: the combination of keys that activate the shortcut.
2. description: a string that describes the shortcut; i.e. what it does.

The suggested_key property is an object with any of the following properties (all strings):

• "default"
• "mac"
• "linux"
• "windows"
• "chromeos"
• "android"
• "ios"

The value of each property is the keyboard shortcut for the command on that platform, as a string containing keys separated by "+". The value for "default" is used on all platforms that are not explicitly listed.

For example:

"commands": {
  "toggle-feature": {
    "suggested_key": {
      "default": "Alt+Shift+U",
      "linux": "Ctrl+Shift+U"
    },
    "description": "Send a 'toggle-feature' event to the extension"
  },
  "do-another-thing": {
    "suggested_key": {
      "default": "Ctrl+Shift+Y"
    }
  }
}

This JSON defines 2 shortcuts:

1. "toggle-feature", accessed with Ctrl + Shift + U on Linux, and Alt + Shift + U on all other platforms.
2. "do-another-thing", accessed with Ctrl + Shift + Y on all platforms.

You could then listen for the "toggle-feature" command with code like this:

browser.commands.onCommand.addListener((command) => {
  if (command === "toggle-feature") {
    console.log("Toggling the feature!");
  }
});

There are these 4 special shortcuts with default actions for which the commands.onCommand event does not fire:

• _execute_browser_action: works like a click on a toolbar button created with browserAction or specified in the browser_action key in the manifest.json key.
• _execute_action: works like a click on a toolbar button created with action or specified in the action key in the manifest.json key.
• _execute_page_action: works like a click on an address bar button created with pageAction or specified in the page_action key in the manifest.json key.
• _execute_sidebar_action: opens the extension's sidebar specified in the sidebar_action manifest.json key.

The availability of these special shortcuts varies between manifest versions and browsers, like this:

For example, this JSON defines a key combination that clicks the extension's browser action:

"commands": {
  "_execute_browser_action": {
    "suggested_key": {
      "default": "Ctrl+Shift+Y"
    }
  }
}

There are two valid formats for shortcut keys: as a key combination or as a media key.

Key combinations must consist of 2 or 3 keys:

1. modifier (mandatory, except for function keys). This can be any of: "Ctrl", "Alt", "Command", or "MacCtrl".
2. secondary modifier (optional). If supplied, this must be either "Shift" or (for Firefox ≥ 63) any one of "Ctrl", "Alt", "Command", or "MacCtrl". Must not be the modifier already used as the main modifier.
3. key (mandatory). This can be any one of:
   • the letters A – Z
   • the numbers 0 – 9
   • the function keys F1 – F12
   • Comma, Period, Home, End, PageUp, PageDown, Space, Insert, Delete, Up, Down, Left, Right

The key is then given as a string containing the set of key values, in the order listed above, separated by "+". For example, "Ctrl+Shift+Z".

If a key combination is already used by the browser (like "Ctrl+P") or by an existing add-on, then you can't override it. You can define it, but your event handler will not be called when the user presses the key combination.

Alternatively, the shortcut may be specified as one of the following media keys:

• "MediaNextTrack"
• "MediaPlayPause"
• "MediaPrevTrack"
• "MediaStop"

Shortcuts can be updated via commands.update(). Users can also update shortcuts via the "Manage Extension Shortcuts" option at about:addons in Firefox, as shown in this video. In Chrome, users can change shortcuts at chrome://extensions/shortcuts.

Define a single keyboard shortcut, using only the default key combination:

"commands": {
  "toggle-feature": {
    "suggested_key": {
      "default": "Ctrl+Shift+Y"
    },
    "description": "Send a 'toggle-feature' event"
  }
}

Define two keyboard shortcuts, one with a platform-specific key combination:

"commands": {
  "toggle-feature": {
    "suggested_key": {
      "default": "Alt+Shift+U",
      "linux": "Ctrl+Shift+U"
    },
    "description": "Send a 'toggle-feature' event"
  },
  "do-another-thing": {
    "suggested_key": {
      "default": "Ctrl+Shift+Y"
    }
  }
}