Silk Performer provides several API functions that allow you
               to work with XML documents and parse and verify XML values of web
               response documents. All these functions are based on an XML dom
               parser that ships with Silk Performer.
            
            注: Most of the BDL functions of the XML API work with handles.
               Handles are numeric values that are internally mapped to XML
               documents/nodes/node lists, ... . When you no longer need
               the handles, be sure to free them. This will keep the used memory as small as
               possible.