Nagaprakash V. Still unable to post by my firefox phone. Getting a newline!

🏒 Lucian Marin Can't do anything about it. You need stock Android keyboad or an iOS device.

🌈 Thomas Rosen You mentioned that only the keyboards are sending the right keycode. What are the other keyboards sending? Are they sending nothing?

🏒 Lucian Marin Nothing or zero for all keys.

🌈 Thomas Rosen Can't you detect that? For example, by simulating a keystroke and waiting for the event. If it's not there after 50ms you could show an submit button.