make-selector.js

function makeSelector(el) {
  var tag, index, stack = [];
  while (el) {
    tag = el.tagName;
    index = 0
    while(el && el.previousSibling){
      el = el.previousSibling;
      if (tag == el.tagName)
        index += 1;
    }
    if(el){
      if(tag)
        stack.unshift(tag + ':eq(' + (index + 0) + ')');  
      el = el.parentNode;  
    } 
  }
  return stack.join(' > ');
}

This seems pretty expensive, why not just give it a unique ID?

It's for use in situations where I have a read only copy of the DOM.