title: Zend Form - dynamic adding subforms
body: <p>I'm working with Zend Form and I need to dynamically (when filling out the form by user) add groups of elements. 
  For example I have form with few fields describing offer and one subform to set offer price. But offer can have more than one price and price is not only 1 element, its composed of</p>
  
  <ol>
  <li>offer regular price</li>
  <li>offer discount price </li>
  <li>offer items count</li>
  </ol>
  
  <p>So there are 3 different elements in one gruop. </p>
  
  <p>I can create elements with javascript but when should I add them to Zend Form Object? </p>