jQuery目标html5标记属性

.alt

section

article

<section id=\"content\" role=\"main\">

  <h1>Main Title</h1>

  <article id=\"post-1\" class=\"post-1 post type-post\">
    .. article content ..
  </article>

  <article id=\"post-2\" class=\"post-2 post type-post\">
    .. article content ..
  </article>

  <article id=\"post-3\" class=\"post-3 post type-post\">
    .. article content ..
  </article>

</section>

$(\'#content article:nth-child(odd)\').addClass(\'alt\');