title: Stop triggering PopOver when title is empty
body: <p>I'm working on a website. You can preview the page in question here: <a href="https://sporedev.ro/pleiade/lobby.html" rel="nofollow noreferrer">https://sporedev.ro/pleiade/lobby.html</a> (don't mind the sounds, they will not autoplay and there will be an option to play/mute them in the future).</p>
  
  <p>I am using <a href="https://github.com/etienne-martin/Mapify" rel="nofollow noreferrer">mapify.js</a> for this project.</p>
  
  <p>I want to enable PopOvers for the plaques near the doors that indicate the room's name.</p>
  
  <p>I managed to activate the PopOvers but the problem is that I can't control the objects for which I want them to appear.</p>
  
  <p>I don't want a PopOver when a someone hovers over other objects than those plaques.</p>
  
  <p>Since the text in the PopOver is placed inside the <code>title</code> of the area I figured that checking if the <code>title</code> is empty to not trigger the PopOver.</p>
  
  <p>Here is the code:</p>
  
  <pre><code>    $("img[usemap]").mapify({
      popOver: {
          content: function(zone){ 
                  return "&lt;strong&gt;"+zone.attr("data-title")+"&lt;/strong&gt;";
          },
          delay: 0.7,
          margin: "15px",
          height: "60px",
          width: "150px"
      }
  });
  </code></pre>
  
  <p>This is the HTML:</p>
  
  <pre><code>&lt;area data-group-id="group-2"  alt="f01_r01" title="Secretariat"  shape="poly" coords="375,391,375,450,381,452,444,452,446,446,446,399,443,394,382,390" nohref  alt="" title="Secretariat" data-hover-class="custom-hover-1"/&gt;
  </code></pre>
  
  <p>I looked on SO and I tried adding some conditions but it didn't end well.</p>
  
  <p>Let me know if you need any additional info.</p>