What authorization method should you use for a JavaScript web application accessing Google Drive's API?

Using an OAuth Client ID is the correct authorization method for a JavaScript web application accessing Google Drive's API because it allows for secure user credential authorization through the OAuth 2.0 protocol. This method involves users logging in with their Google accounts and granting permissions to the application without sharing their passwords.

When a user authenticates using OAuth, the application receives an access token, which can then be used to make authorized requests to the Google Drive API on behalf of that user. This process enhances security by managing user credentials effectively and providing fine-grained permissions. It also supports scenarios where multiple users are accessing the application and each may have different permissions based on their Google accounts.

In contrast, creating an API key is suited for server-to-server communication where user identity is not a consideration, which is not appropriate for a web application that interacts with user data. SAML tokens are typically used in enterprise environments for single sign-on (SSO) scenarios rather than public web applications. A service account is designed for server-to-server interactions, making it unsuitable for a web app that requires user interaction and consent.