title: Thousands of items in multiple dropdown menus
body: <p>A client has given me a task to do that I've not done before, and so I'm looking for the best way to do it. They have a form they want users to fill in, but for one field, they want an option of thousands to be placed into three dropdown menus.</p>
  
  <p>For example:</p>
  
  <p><img src="https://i.stack.imgur.com/bZj6E.gif" alt="enter image description here"></p>
  
  <p>So a user will only be able to choose a Venue once they've chosen a City, only a City once they'd chosen a State. (A nice way to break up the thousands of options.)</p>
  
  <p>I suppose I could this quite easily using POSTBACKs and a simple database, but I imagine that doing something with AJAX and a simple database would be the slicker solution.</p>
  
  <p>Are there any other ways that this problem might be tackled? If not, does anyone have any links to tutorials or code snippets I could grab? Secondly, how long do you think it would take <strong>you</strong> to implement such a system? </p>
  
  <p>I've never done this before so I'm hoping to avoid as many unforeseen pitfalls as possible. Thanks.</p>