A method, system and an article of manufacture tangibly embodying a computer readable program for protecting Web application data between a server and a client. A response created by the Web application for the client is backed up and modified by adding capturing code for capturing a user action, user data of the client, or combination thereof. The modified response is sent to the client and a request submitted by the client and the user action and/or user data captured by the capturing code is received. A verifying request is generated according to the received user action and/user data captured by the capturing code and the backup of the response. The request submitted by the client is verified according to the verifying request and the verified request is sent to the Web application of the server.