XML DOM Parsing, What if you don't know what the file looks like?

I have been trying something like this, but wasn't able to get it right, as i always got errors. I am trying to recieve an XML document but i don't know what exactly it will look like or how many childs it has, and what not. So the tree is sort of like:
- ffff
__-fff
___-fffff
___-fffff
___-fffff
_____-ff
_____-ff
___-fffff
__-fff
__+fff
__+fff

In other words its a complex XML file, and you don't know how it's gonna turn out. I have been trying to find a way to test for child nodes, i mean if it has a child then go there, if not stick in the upper level. But i'm not sure how to navigate thru the DOM.

for(i = 0; i < XMLobj.childNodes.length; i++){
          try {
            debug("Attempting First Child");
            XML.push(XMLobj.childNodes[i].firstchild.nodeName+': '+XMLobj.childNodes[i].firstchild.nodeValue);
          } catch(e){
            debug("Attemting Second child - Error: "+e);
            try {
              XML.push(XMLobj.childNodes[0].childNodes[i].firstchild.nodeName+': '+XMLobj.childNodes[0].childNodes[i].firstchild.nodeValue);
            } catch(e) {
              debug("Second Child Node Failed: "+e);
              try {
                XML.push(XMLobj.childNodes[0].childNodes[0].childNodes[i].firstchild.nodeName+': '+XMLobj.childNodes[0].childNodes[0].childNodes[i].firstchild.nodeValue);
              } catch(e) {
                debug("Third Child Node Attempted, Failed: "+e);
              }
            }
          }
        }

Code (markup):

If anyone already has a function. Please do tell
But basically i want a DOM script to actually parse all nodeNames and set them equal to the value and display them like a tree or just plain bullets.