Why is data being deleted from the database on an application made on apache cordova?

Question

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Hello.
There is an application. The data is stored in a webSQL database (a database in a browser). To make it clearer, it connects like this var db = window.openDatabase("Database", "1.0", "Cordova Demo", 200000);
The application is running successfully.
But some users lose data. I sin on Cleaner programs. How can I make sure that the data
is not deleted?