title: Alert Message with external js file
body: <p>I have a external test.js file with code:</p>
  
  <pre><code>$(document).ready(function() {
      alert("I am an alert box2!");   
  });
  
  
  function show_alert()
  {
      alert("hihi");
  }
  </code></pre>
  
  <p>In my .html, I have included test.js, jquery file and there is a button. When click on it, <code>show_alert()</code> function will be called and it works. However, The message "I am an alert box2!" is not fired.<br>
  Also, if I put the document.ready function in my .html with <code>&lt;script&gt;... &lt;/script&gt;</code>. It works. What wrong with my code? External file not support?</p>