title: Button on click w/ selected value of <select> as parameter
body: <p>I am new to web development and I'm trying to do this: 
  I have a <code>&lt;select&gt;</code> and I want the value of the selected option to be one of the parameters of a method that is called whenever a button is clicked.</p>
  
  <p>So for example: </p>
  
  <pre><code>&lt;select id="instructorSelector"&gt;
     &lt;option value='abrown@gmail.com'&gt;Anna Brown&lt;/option&gt;
     &lt;option value='jdoe@gmail.com'&gt;Jane Doe&lt;/option&gt;
     ...
  &lt;/select&gt;
  
  &lt;button onclick="sendEmail(($('#instructorSelector').val()),...,...)" type="button"&gt;Send Email&lt;/button&gt;
  </code></pre>
  
  <p>The problem with this is that it doesn't seen to detect when I've actually selected someone. I'm using freemarker templates but a general response as to how I should do this would be helpful too. </p>
  
  <p>Also, how could I make it so the button is not clickable (or even visible) until the user actually selects something from the <code>&lt;select&gt;</code> ? </p>
  
  <p>Thanks in advance! Sorry if this is an overly simple question. </p>