Offset is returning null, why?

Offset is returning null, why?

In my actual web page offset() was returning values that were much too high. Yet when I tried to recreate a simple example offset() now returns null. Below is the code and markup. Any ideas.

Thanks,
Jason

http://jsbin.com/udowu

  1. <style>
      .header{
          height: 65px;
          background-color: #3A4a5d;
          width: 100%;
          margin-bottom: 10px;
       }
      .menu{
        background-color:#F6F6F6;
        float: left;
        height: 400px;
        padding: 5px;
        position: absolute;
        width: 200px;
      }
      .content{
         margin-left: 225px;
      }
      .section{
        margin-top: 15px;
        background-color: grey;
      }
    </style>
    </head>
    <body>
      <div class="header">Header</div>
      <div class="menu">Sidebar</div>
      <div class="content">Content
        <div class="section">section 1</div>
        <div class="section">section 2</div>
        <div class="section">section 3</div>
      </div>
    </body>































  1. $(document).ready(function(){
      var s = $(".section :last");
      var offset = s.offset();
      alert(offset);
    });