I Need a example for create a file with the object Xmlhttprequest

Hi.
I need help for create a page.html with the object xmlhttprequest, my page.html have a grid with the component of activewidgets, but I need conect my page a file.java, and this file.java conect a base.xml, for update my base.xml and refresh my page.html with the grid, the problem is wath I unknow to do that.

Some one have a example unloadable para see the code, please I need you help.