I have already found many answers about this like link But I don't think it really solves my problem, I still can easily get my database instance in client side:
firebase.initilizeApp(config);
db = firebase.firestore();//db can be considered as an instance
Then simply type code in Chrome console:
db.collection("abc").where("id","===","1").get().then(function(){//do something})
to get my data.
However I still want the client side is able to do CRUD but only through the page events like click or drag or something else.
So in such situation, is it possible to achieve it?