Why i got [object HTMLParagraphElement]
<p>I am a newbie.
Here is my code:</p>

<pre><code>&lt;html&gt;
  &lt;head&gt;
    &lt;script type="text/javascript"&gt;
      function replyOne () {
        document.getElementById("comment_content").value = document.getElementById("username")
      }
    &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;p id="username"&gt;Jack&lt;/p&gt;
    &lt;textarea id="comment_content" &gt;&lt;/textarea&gt;
    &lt;button onclick="replyOne()"&gt;Copy Text&lt;/button&gt;
  &lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>I expect when i click the button, it can copy 'Jack' to the textarea.<br>
But now it just write '[object HTMLParagraphElement]'.<br>
I tried google it but din't got the right anwser, so i hope someone can help me, thanks a lot :)</p>
