function isVoid(node) {
  return node && /^BR|^IMG|^HR|^IFRAME|^BUTTON|^INPUT|^AUDIO|^VIDEO|^EMBED/.test(node.nodeName.toUpperCase());
}
ex) br, col, embed, hr, img, input, ...
@see http://www.w3.org/html/wg/drafts/html/master/syntax.html#void-elements