title: jQuery find('img').attr('src') does not work
body: <p>The following code will not work:</p>
  
  <p><code>find('img').attr('src')</code></p>
  
  <p>I want hover on aside area and image change on/off.</p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;aside style="width:200px;height:300px;text-align:center;"&gt;
    &lt;img class="img" src="imgs/photo_off.png" alt="" &gt;
  &lt;/aside&gt;
  </code></pre>
  
  <p><strong>JavaScript</strong></p>
  
  <pre><code>$("aside").hover(
      function () {
          $(this).find('img').attr('src') = $(this).find('img').attr('src').replace("_off", "_on");
      },
      function () {
          $(this).find('img').attr('src') = $(this).find('img').attr('src').replace("_on", "_off");
      }
  );
  </code></pre>