get firstChild of div
<p>I am trying to get the text of the span element. I have tried two methods using <code>querySelectorAll</code> and <code>getElementByClassName</code> but both give me the error "Uncaught TypeError: Object # has no method 'getElementsByTagName'" how do I go about getting the text of the span element?</p>

<p><strong>javascript</strong></p>

<pre><code>var interstitial; 

// 1st attempt
interstitial = document.querySelectorAll('div.top_bg').getElementsByTagName("span");
// 2nd attempt
interstitial = document.getElementByClassName('top_bg')[0].getElementsByTagName("span");

if (interstitial) {
  console.log(interstitial[0].firstChild.innerHTML);
}
</code></pre>

<p><strong>html</strong></p>

<pre><code>&lt;div class="top_bg"&gt;
  &lt;span style="font-size:14px;line-height:30px"&gt;The text I am trying to get.&lt;/span&gt;
&lt;/div&gt;
</code></pre>
