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You need to implement both of these things.
a) For a notification you can either use a timer based approach (querying the server every ...) or Websockets. It depends on your usecase and how often you need to query the backend. Timer based are usually simpler since you just need to implement a rest service to provide the notification/update.
b) Backup: I think, "autobackup" is only available for Liferay Cloud, so you also need to implement this yourself. I would implement a rest service that starts the the backup script, maybe even as a backend job. Note: For some usecases it might even be sufficient to do an export of the current site.

for the first part :
i found the java script code of auto resfresh but i don't know when i put the code in which js file in the liferay files?
for the second part
i don't understand  your second part  successfully but i try to use mysqldump to backup the DB and then make bat file to call it in task schedule in the pc to do the back file auto every day
this is right idea for liferay DB ?

1: you found some code that does something, and want to know what to do with it? That's not answerable, you'll need to be more detailed. And it doesn't look like this belongs in a thread about backup.

2: More important than a Backup is your ability to restore. Backup instructions are here. Use them, then take the data you've backed up, restore them on a totally unrelated machine and validate that you're able to build a fully working system. Don't trust anyone on a free forum to tell you "Yeah, that's it", only to discover that you forgot saving your file-based document repository, or that reindexing takes 10h for the amount of data you store.

And IMHO, calling a Backup "Backup" should only be allowed when it's frequently tested that you're able to restore. Otherwise it's a "random sample of data that you hope to be useful in case of a failure", but not a "backup".