How to Reverse Ajax in DWR

AJAX elements added to a Web page are designed to query a server when the page loads. Direct Web Remoting, sometimes referred to as DWR, lets users reverse this system so that a server can transmit information to a Web page via an AJAX element, which is otherwise difficult to achieve. This feature is useful for anyone who needs to continually upload a Web page with data that is aggregated from multiple sources and sent to a single server.

Instructions

1. Open your website's "web.xml" file by right-clicking on the file and choosing "Open With," then clicking "Notepad." The file will automatically open in the program.

2. Add the following code to the end of the file:

   <servlet>
   <servlet-name>dwr-invoker</servlet-name>
   <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
   <init-param>
   <param-name>activeReverseAjaxEnabled</param-name>
   <param-value>true</param-value>
   </init-param>
   </servlet>

3. Click "File," then "Save" to save the changes you made to the file, then close Notepad.

4. Open the Web page that has the AJAX element you want to reverse in Notepad. Add the following line of code to the end of the AJAX script:

   dwr.engine.setActiveReverseAjax(true);

5. Click "File," then "Save" to save the changes, then close Notepad.

References

• Direct Web Remoting: How to Reverse AJAX in DWR