This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
the HTTP protocol dictates that there will a response, but it may not be the response that you want eg the response is sent immediately but the server has not finished processing yet.
HTTP requires the client to pull information, therefore (typically) the client would then need to poll the server waiting for the real response to be sent from the server