code: function preventDefaultOnPoundLinkClicks() {
    document.addEventListener('click', function(e) {
      var anchor = findAncestor(/** @type {Node} */(e.target), function(el) {
        return el.tagName == 'A';
      });
      // Use getAttribute() to prevent URL normalization.
      if (anchor && anchor.getAttribute('href') == '#')
        e.preventDefault();
    });
  }
docs: TODO(dbeam): DO NOT USE. THIS IS DEPRECATED. Use an action-link instead.
  Call this to stop clicks on <a href="#"> links from scrolling to the top of
  the page (and possibly showing a # in the link).