function C(
  c, // className
  n, // nodeList
  r, // result
  i  // index
){
  // initialize result array
  r = r || [];
  // walk nodeList or an array containing "this" (node from which it is called)
  for (i in n=n || !i && [this])
    // recursively iterate over children (use .childNodes for document, alas
    // this breaks the 140bytes barrier)
    C(c,(i=n[i]).children,r,1),
    // create RegExp through eval to test for className, add to result if present
    eval('/\\b' + c + '\\b/').test(i.className) && r.push(i);
  // return result
  return r
}