title: How to detect page scroll to a certain point in jQuery?
body: <p>Imagine this is my page:</p>
  
  <pre><code>&lt;p&gt;hello&lt;/p&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;br /&gt;
  &lt;p class="myPara"&gt;My Paragraph&lt;/p&gt;
  </code></pre>
  
  <p>How can I alert a message when the user has scrolled down to the paragraph with the class "myPara" and not before then?</p>