title: show two components in vuejs, but only one got displayed, why?
body: <p>vuejs newbie got a question, I created two components, 'hello' and 'world', when display then two in the html, only one got displayed, why? Thanks,</p>
  
  <p><a href="https://jsfiddle.net/aaoehLqe/3/" rel="noreferrer">https://jsfiddle.net/aaoehLqe/3/</a></p>
  
  <pre><code>&lt;div id="app"&gt;
      &lt;hello :msg="'test1'" /&gt; 
      &lt;world :msg="'test2'" /&gt;     
  &lt;/div&gt;
  </code></pre>