These are the findings that I had in bullet points:
- It is mentioned that WebSQL has been deprecated but is still supported by Android and iOS. They do not have any plan to remove it anytime in the future.
- The SQLite alternative is seemed to be supported by individuals/small group as well as those who developed WebSQL. There is no clarity about the support and future as well.
- IndexedDB seems good but is not supported by iOS
- Some opinions said that WebSQL is deprecated simply because it does not fulfill a standard for client side storage but the standard does not really exist and not accepted by all parties.
- SQLite also does not fullfil the standard
References:
https://softwareengineering.stackexchange.com/questions/220254/why-is-web-sql-database-deprecated
https://www.reddit.com/r/SQL/comments/8woehg/sqlite_being_deprecatedreplaced_as_database/
https://cordova.apache.org/docs/en/latest/cordova/storage/storage.html