title: How to get selected value from dropdownlist using chosen.js
body: <p>I am trying to get two parameters from dropdown list change event. Dropdown list uses chosen.js</p>
  
  <p>First I would like to get a name of the dropdown list
  Second I would like to get a value of an item that has been selected</p>
  
  <p>I found this code in documentation:</p>
  
  <pre><code>$('.my_select_box').on('change', function(evt, params) {
      do_something(evt, params);
  });
  </code></pre>
  
  <p>but when I trigger it, params are undefined. Have been looking everywhere, but cannot find out how to do it. Can you help please?</p>