title: fade in background jquery
body: <p>I'm trying to fade some images on the background of my site but isn't working T_T .
  Thanks in advance !</p>
  
  <p>HTML :</p>
  
  <pre><code>&lt;body&gt;
      &lt;div id="menu1"&gt;&lt;/div&gt;
      &lt;div id="menu2"&gt;&lt;/div&gt;
      &lt;div id="menu3"&gt;&lt;/div&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>CSS :</p>
  
  <pre><code>body {
      background-color: #1f304e;
      background-image: url('images/bg.jpg');
      background-repeat: no-repeat; 
      background-attachment:fixed;
      background-position: center 0px;
  }
  </code></pre>
  
  <p>JQuery :</p>
  
  <pre><code>$('#menu1').click(function(){
      $(body).animate({background : url('images/bg1.jpg') }, 600);
  }); 
  $('#menu2').click(function(){
      $(body).animate({background : url('images/bg2.jpg') }, 600);
  }); 
  $('#menu3').click(function(){
      $(body).animate({background : url('images/bg3.jpg') }, 600);
  });
  </code></pre>