XPath学习5：descendant-or-self

descendant-or-self  选取当前节点的所有后代元素（子、孙等）以及当前节点本身

descendant-or-self跟descendant类似，多了节点本身。

     /AAA/BBB/descendant-or-self::*    选择/AAA/BBB本身及所有后代元素

   <AAA> 
     <BBB> 
          <DDD> 
               <CCC> 
                    <DDD/> 
                    <EEE/> 
               </CCC> 
          </DDD> 
     </BBB> 
     <CCC> 
          <DDD> 
               <EEE> 
                    <DDD> 
                         <FFF/> 
                    </DDD> 
               </EEE> 
          </DDD> 
     </CCC>

      //CCC/descendant-or-self::*    选择CCC的所有后代元素及本身

   <AAA> 
     <BBB> 
          <DDD> 
               <CCC> 
                    <DDD/> 
                    <EEE/> 
               </CCC> 
          </DDD> 
     </BBB> 
     <CCC> 
          <DDD> 
               <EEE> 
                    <DDD> 
                         <FFF/> 
                    </DDD> 
               </EEE> 
          </DDD> 
     </CCC> 
  </AAA>