Patent attributes
A computer-implemented method includes receiving, by a proxy device, a document from a service provider in response to a request to the service provider from a client device. The proxy device injects into the document event monitoring code for monitoring user actions on the client device. The proxy device sends the document with the event monitoring code to the client device. The event monitoring code intercepts a user request for a file upload event using a client-side application on the client device. The proxy device receives a client request including file information regarding the file upload event from the event monitoring code. The proxy device determines whether the file upload event should be allowed or blocked based on the received file information and stored policy data.