Since Ajax applications follow the client-server architecture principle, a component is necessary both within the web browser as well as on the appropriate server that allows Ajax-based communication.
Here, two types of platforms can be distinguished:
Direct Ajax implementations: these represent the client API for direct communication of data. This is to be realized on the server in addition to the initial page displays an additional entry point for the transmission of data.
Indirect Ajax implementations: New HTML fragments are sent from the server to the client, to complement the existing page or to replace parts of it. Usually the entire page to be displayed is rebuilt on the server, and only transfers the relevant differences to the client.
Both methods have advantages and disadvantages. While the direct use often saves server side resources, the indirect variant simplifies the implementation.
The actual logic or process flow of the application is stored on a server. This happens for example in the form of EJBs. NET components or in the form of script components, for example, as part of the scripting language Ruby.
The Ajax concept itself requires no specific technique by which the server-side program logic must be implemented. Both the server and the application logic is called in the context of Ajax as a server platform.
A key task of the server with Ajax applications is the provision of the necessary components in the browser.
Since due to the security settings of the browser, cross-site scripting is not allowed (same-origin policy), the web server has to provide and therefore assume the function of a proxy computer and data from other servers for the client.