What application is good for writing and running offline Javascript applications on Android

Answer 1

if by running JavaScript apps you mean JS code offline, then ScriptIt is a nice app, you can try using that

https://scriptit-app.com/tag/android/

https://play.google.com/store/apps/details?id=com.rbowman.scriptit

Answer 2

I use: JSide app for simple javascript coding, and Droidscript app, for make apps on android bases on javascript

https://play.google.com/store/apps/details?id=net.nizarmah.jside

https://play.google.com/store/apps/details?id=com.smartphoneremote.androidscriptfree