title: How can I know which radio button is selected via jQuery?
body: <p>I have two radio buttons and want to post the value of the selected one.
  How can I get the value with jQuery?</p>
  
  <p>I can get all of them like this:</p>
  
  <pre><code>$("form :radio")
  </code></pre>
  
  <p>How do I know which one is selected?</p>