title: jssor slider error in bullet navigation
body: <p>hi i use jssor slider for making a slider in ebay template this is the first time i'm using it. so i'm just making a practice locally. the slider is working fine but when i add the bullet navigator it shows the following error</p>
  
  <pre><code>Uncaught Error: Navigator item prototype not defined.
  </code></pre>
  
  <p>here is my code so far...</p>
  
  <pre><code> &lt;script src="jssor.js"&gt;&lt;/script&gt;
    &lt;script src="jssor.slider.js"&gt;&lt;/script&gt;
    &lt;script&gt;
        jssor_slider1_starter = function (containerId) {
         var options = {
  
             $BulletNavigatorOptions: {
              $Class: $JssorBulletNavigator$,
              $ChanceToShow: 2
          }
      };
      var jssor_slider1 = new $JssorSlider$(containerId, options);
    };
  &lt;/script&gt;
  &lt;/head&gt;
   &lt;body&gt;
     &lt;div id="slider1_container" style="position: relative; top: 0px; left: 0px; width: 600px; height:   300px;"&gt;
  
      &lt;!-- Slides Container --&gt;
      &lt;div u="slides" style="cursor: move; position: absolute; overflow: hidden; left: 0px; top: 0px; width: 600px; height: 300px;"&gt;
          &lt;div&gt;&lt;img u="image" src="blue.jpg" /&gt;&lt;/div&gt;
          &lt;div&gt;&lt;img u="image" src="purple.jpg" /&gt;&lt;/div&gt;
          &lt;div&gt;&lt;img u="image" src="red.jpg" /&gt;&lt;/div&gt;
      &lt;/div&gt;
  
    &lt;!--navication bullets--&gt;
      &lt;div u="navigator" class="jssorb01"&gt;
        1
     &lt;/div&gt;
  
      &lt;div u="navigator" class="jssorb01"&gt;
       2
      &lt;/div&gt;
  
      &lt;div u="navigator" class="jssorb01"&gt;
        3
      &lt;/div&gt;
        &lt;!--/navigation bullets--&gt;
        &lt;!-- Trigger --&gt;
        &lt;script&gt;jssor_slider1_starter('slider1_container');&lt;/script&gt;
       &lt;/div&gt;
  </code></pre>
  
  <p>and please give an example of how to use it in ebay listing template...</p>