It is usually more susceptible to bugs than the back end. The combination of a lack of control over the environment your code runs in and javascript's weak typing give it that extra dose of fun.
These days front-end =/= Javascript[2] by a long shot (maybe yours is, but blame the person who made that decision for your project).
1. I don't know if that's still true. If it is, then I'm glad I no longer have to deal with MySQL.
2. GWT had strong-typing since forever. Not that I'm endorsing it, but it's still front end. I do recommend TypeScript
That's still true, as I recall. To avoid this nonsense, you need to change the sql_mode - either globally in the server config, or only within your session by issuing an SQL query.
Documentation: https://dev.mysql.com/doc/refman/5.6/en/sql-mode.html#sqlmod...