title: filter out nodes with certain id expression using xpath
body: <p>Currently I've got following example xpaths of the nodes I want:</p>
  
  <pre><code>/html
   /body
    /div[@id='wp']
     /div[@id='ct']
      /div
       /div[@id='threadlist']
        /div[2]
         /form
          /table
           /tbody[@id='normalthread_1174131']
            /tr
             /th
              /a
  </code></pre>
  
  <p>And something I don't need:</p>
  
  <pre><code>/html
   /body
    /div[@id='wp']
     /div[@id='ct']
      /div
       /div[@id='threadlist']
        /div[2]
         /form
          /table
           /tbody[@id='stickthread_1174132']
            /tr
             /th
              /a
  </code></pre>
  
  <p>Of course, I could select them all using:</p>
  
  <pre><code>/html/body/div[@id='wp']/div[@id='ct']/div/div[@id='threadlist']
                                             /div[2]/form/table/tbody[@id]/tr/th/a
  </code></pre>
  
  <p>But I only want to select nodes with id normalthread_xxx. As each node has different id. In other words, the target page may have following nodes:</p>
  
  <pre><code>/html/body/div[@id='wp']
             /div[@id='ct']
              /div/div[@id='threadlist']
                   /div[2]/form/table/tbody[@id='normalthread_1174133']
                                      /tr/th/a
  
  /html/body/div[@id='wp']
             /div[@id='ct']
              /div/div[@id='threadlist']
                   /div[2]/form/table/tbody[@id='normalthread_1174134']
                                      /tr/th/a
  </code></pre>
  
  <p>Can we have something similar to </p>
  
  <pre><code>/html/body/div[@id='wp']
             /div[@id='ct']
              /div/div[@id='threadlist']
                   /div[2]/form/table/tbody[@id='normalthread_XXX']
                                      /tr/th/a
  </code></pre>
  
  <p>, in order to filter all the nodes here?</p>