title: Selecting an attribute from an element without a name
body: <p>I have this in my HTML </p>
  
  <pre><code>&lt;meta name="title" content="Hello World"/&gt;
  &lt;meta property="article:published_time" content="2014-11-20T11:00:01+00:00"/&gt;
  </code></pre>
  
  <p>I want to access the article:published_time content data.</p>
  
  <p>In console this works:
  <code>document.getElementsByTagName("meta")['title']</code></p>
  
  <p>But I can't get "article:publish"</p>
  
  <pre><code>document.getElementsByTagName("meta")['article:published_time']
  </code></pre>
  
  <p>Shows as undefined. I tried escaping with "\\"</p>