multiple select

HTML

<select multiple id="myselect">
  <option value="New York">New York</option>
  <option value="Londres">Londres</option>
  <option value="Berlin">Berlin</option>
  <option value="Zurich">Zurich</option>
</select>

JavaScript

$(document).ready(function(){
    $('#myselect').on('change', function(){
        window.console.log($(this).val());
    })
})