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 Optional: the combination of keys that activate the shortcut.
2. description Optional: a string that describes the shortcut, i.e., what it does.

The suggested_key property is an object with any or none of these 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 aren't explicitly listed. If `"default"`` isn't included, the command doesn't have a keyboard shortcut on any platform not included, unless a shortcut is configured by the user or through the commands.update API.

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"
    }
  },
  "do-something-else": {
    "suggested_key": {
      "linux": "Ctrl+Shift+P"
    }
  },
  "do-nothing-yet": {}
}

This JSON defines these 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.
3. "do-something-else", accessed with Ctrl + Shift + P on Linux only, and no default shortcut on other platforms.
4. "do-nothing-yet", sets no keyboard shortcut but enables a shortcut to be set by the user or with the commands.update API.

You can listen for the commands with code like this, in this case for the "toggle-feature" command:

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

There are 4 special shortcuts with default actions for which the commands.onCommand event doesn't 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"
    }
  }
}