Using Steps:
Click alt key -> Hold it (important) -> Select words on web pages -> Translated results show up

No disturb to your normal actions on web pages.
Auto detect browser language.
Support over 40 languages.
Night mode.
Resize results box.

Install

• License: Mozilla Public License 2.0
• Weekly downloads: 16
• Average daily users: 1110
• Rating: 2.4138/5 of 29 ratings
• Created: 2015-05-11 01:23:18
• Last updated: 2018-05-12 07:25:09
• Homepage:
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/google-selection-translate-for/
• API: jid1-f7dnBeTj8ElpOQ@jetpack