It looks like you can extend the context menu of chrome[1], safari[2], IE[3], and firefox[4].

1.https://developer.chrome.com/extensions/contextMenus 2.https://developer.apple.com/library/content/documentation/To... 3.https://msdn.microsoft.com/en-us/library/aa753589(v=vs.85).a... 4.https://developer.mozilla.org/en-US/Add-ons/SDK/Tutorials/Ad...