Hide asking confirmation on login

Yes, your app can store and re-use the resulting access token for each user, so that it doesn't need to send the user through the OAuth app authorization flow each time. 

Exactly how you do so depends on your platform, and the library/SDK you're using, so I recommend referring to the relevant tutorial and/or documentation.

Hello Gregory, the platform I am using is JavaScript. The ide i am using is wakanda(open source for both server side and client side js). The method i am using for authorization is by calling 

https://www.dropbox.com/1/oauth2/authorize/?response_type=token&&client_id='client_Id'&&redirect_uri=url_path".

Could you please suggest a method for hiding the confirmation box on each log in ?

The result of the OAuth 2 authorize URL you posted is an access token. When that access token (which is just a string) is returned to your app, you can store and re-use it in the future, so that you don't have to send the user to that authorize URL again. Since the access token is just a string, you can store is in whatever data persistence layer you have (i.e., your database, or the browser's local storage, etc.).

Ok. I will try that.

But the access token generated will be different for different users right? I am not having a specific  login to the application for getting userid. The only authorize call is to the dropbox. If multiple users are using this application and if one particular accesstoken is stored and fetched from the storge, all the items be stored into that particular account.

That's correct, access tokens are user-specific. It sounds like you mean that your app doesn't have its own user model, and is relying on the Dropbox app authorization flow as authentication. First, it's worth noting that OAuth 2 is for authorization, not authentication, e.g., see these blog posts. Anyway, if you do use this for that anyway, to avoid unnecessarily putting the user through this flow, you can store the necessary data, e.g., the access token, in their cookies or local storage. If and only if you don't find that, you can send them the flow. Also, check out the documentation for the force_reapprove parameter on /oauth2/authorize. By default, Dropbox will automatically redirect the user through the flow when possible.

Thanks Gregory for your support.