title: Pattern attribute on input element allows empty values?
body: <p>I'm requesting the user give me a nickname that is at least 3 characters and at most 30 characters and only contains letters and numbers.</p>
  
  <pre><code>&lt;form&gt;
      Nick: &lt;input type="text" name="nick" pattern="[A-Za-z0-9]{3,30}"&gt;
      &lt;input type="submit" value="Join lobby"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>The problem I'm having is that empty forms are accepted.<br>
  As expected, strings that have a length of 1, 2, or 31+, or contain punctuation, do not pass.  But if they just don't put anything into the box, it <em>is</em> accepted.</p>
  
  <p>How can I fix this?</p>