title: Custom div attribute catch changes
body: <p>I have a div with custom attribute <code>posx</code></p>
  
  <pre><code>&lt;div class="js__scroll__canvas" posx="0"&gt;
  </code></pre>
  
  <p>Another js plugin set dynamic value to posx on scroll.</p>
  
  <p>I try to catch <code>posx</code> is change.</p>
  
  <pre><code>$(".js__scroll__canvas").attr( "posx" ).change(function() {
      alert( "Handler for .change() called." );
  }); 
  </code></pre>
  
  <p>Nothing alerts. How to catch it? Help please</p>