title: MVC (5) Populate a dropdown based on another
body: <p>I know I can make a dropdown with a list of <code>SelectedListItem&gt;</code> and <code>@Html.DropDownList("someID")</code> and os on..</p>
  
  <p><strong>My question is</strong>, what if you had 2 dropdowns, and the second dropdown depended on the selected item from the first dropdown? </p>
  
  <p>How do you populate it? With JS? How would you go about it? 
  Would you change the populate with another list, change the whole dropdown or maybe have a partialview for each dropdown combination, so it's a matter of replacing with the right dropdown.</p>