getElementsByTagName

gistfile1.js

/* vim: set ft=javascript: */
// http://dean.edwards.name/weblog/2009/12/getelementsbytagname/
function getElementsByTagName(node, tagName) {
  var elements = [], i = 0, anyTag = tagName === "*", next = node.firstChild;
  while ((node = next)) {
    if (anyTag ? node.nodeType === 1 : node.nodeName === tagName) elements[i++] = node;
    next = node.firstChild || node.nextSibling;
    while (!next && (node = node.parentNode)) next = node.nextSibling;
  }
  return elements;
}