title: How to change only text inside a div which has other divs
body: <p>I have html below. What I want to do depends on some conditions. I want to keep changing the text which is <code>Sometitle</code>.</p>
  
  <pre><code>&lt;div id="header"&gt;
      Sometitle
      &lt;div&gt;
          &lt;div&gt;
              aa
          &lt;/div&gt;
          &lt;div&gt;
              bb
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I tried using Jquery below but it removes the other divs also.</p>
  
  <pre><code>$("#header").text("Its a thrusday today !");
  </code></pre>
  
  <p>How do I get this done? I cannot modify this HTML in any case. I just have to use jquery and get this thing done.</p>
  
  <p>Here is a jsfiddle I created : <a href="http://jsfiddle.net/qYUBp/" rel="noreferrer">http://jsfiddle.net/qYUBp/</a></p>