firefox - Search for the exact child node with HTML using javascript

getElementsByTagName("*") will get you the child nodes in Depth First Search in Pre-order. The problem is if I search for a string inside the node's HTML, there is no way to tell the same is inside another child node that is going to be returned by the getElementsByTagName("*"). So, is there any way to iterate nodes from leaves to root?
Most probably a DFS-Post order will do the trick!

For example:

  

    

      

        textmore text

      
    
  

If we are searching for more text, then innerHTML of first element for the result as well as all the subsequent elements will match. But I want only the exact child to match the string. If we are starting from the leaves, then we can break away after finding the text.

Any other idea?