This version of the web client for the contacts samples is based around java servlet technology - XMLHTTP. This technology is useful as a sample because it is generic and should work with most browser and most server platforms.
Lets start with a request or submission. View the source html for the add a company page. This is a simple html form except for the two hidden input fields. The first one is the component field. This value matches the role property in the subscriber component. The second field is the rootTag field. This field is used when converting the submitted form to XML and also matches the tag property of the subscriber.
The form is submitted to a java servlet (using the form action code) that converts the form fields submitted into an XML document. The document produced is a one level document using the rootTag value as the root tags. Each field submitted is then converted into one node of the document. The resulting document is then sent to ComponentX and a reply is received by the servlet that then does and XSL transformation required and then sends the result (usually pure html) back to the browser.