 <p>That's one of the downsides of having API's that returns <code>null</code>. The <a href="http://en.wikipedia.org/wiki/Null_Object_pattern" rel="nofollow">Null Object</a> pattern could have been used here to simplify the API, relieving the clients from dealing with null values.</p> <p>".offset() returns an object containing the properties top and left"</p> <p>Therfore, you can do something like:</p> <pre><code>var menuOffset = menu.offset() || { top: 0, left: 0 }, menuTop = menuOffset.top + 100; $('.other').css('top', menuTop + 'px'); </code></pre>