why the alert has no value?
<pre><code>&lt;title&gt;New Web Project&lt;/title&gt;
        &lt;script type="text/javascript"&gt;
            var paras = document.getElementsByTagName("p");
            for (var i=0; i&lt; paras.length; i++) {
            var title_text = paras[i].getAttribute("title");
            if (title_text != null) {
                alert(title_text);
                }
            }

        &lt;/script&gt;
    &lt;/head&gt;
    &lt;body&gt;
        &lt;h1&gt;New Web Project Page&lt;/h1&gt;
        &lt;p title="test"&gt; This is just a test&lt;/p&gt;
    &lt;/body&gt;
</code></pre>

<p>why the alert has no value? i feel it should popup the text <code>test</code>.</p>
