title: How to extend Javascript Prototype?
body: <p>I instantiate a function from my template with</p>
  
  <pre><code>new Product.Image({
          "title": document.querySelector('#image-title')
      });
  </code></pre>
  
  <p>But now I need to extend "Product.Image" e.g. with "Product.BetterImage"</p>
  
  <pre><code>new Product.BetterImage({
          "title": document.querySelector('#better-image-title')
      });
  </code></pre>
  
  <p>My original class starts like this:</p>
  
  <pre><code>Product.Image = function (options) {
    //do something
  }
  Product.Image.prototype = new Product.Data();
  </code></pre>
  
  <p>Now I tried to copy it to extend "Product.Image":</p>
  
  <pre><code>Product.BetterImage = function (options) {
    //do something
  }
  Product.BetterImage.prototype = new Product.Image();
  </code></pre>
  
  <p>But when I call my template to initiate it I got the following error:</p>
  
  <pre><code>Uncaught TypeError: Product.BetterImage is not a constructor
  </code></pre>
  
  <p>What am I missing here or what have done wrong?
  Can anyone explain me what's wrong here?</p>