title: On a multi-select form, on submit select all options if none were selected
body: <p>Using jQuery/Javascript, when a user clicks submit I need to validate if at least one option has been chosen on a select form, and one hasn't been chosen, I need them all to be submitted.</p>
  
  <p>So on a form like this:</p>
  
  <pre><code>&lt;form action="http://example.com" method="get" id="carfare" name="mycarform"&gt;
  &lt;select name="car" id="carchoice" multiple&gt;
    &lt;option value="volvo"&gt;Volvo&lt;/option&gt;
    &lt;option value="saab"&gt;Saab&lt;/option&gt;
    &lt;option value="opel"&gt;Opel&lt;/option&gt;
    &lt;option value="audi"&gt;Audi&lt;/option&gt;
  &lt;/select&gt;
  &lt;input id="carsubmit" type="submit"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>If the user clicks the submit button without choosing any options, I need it to return:
  <a href="http://example.com/?car=volvo&amp;car=saab&amp;car=opel&amp;car=audi" rel="nofollow">http://example.com/?car=volvo&amp;car=saab&amp;car=opel&amp;car=audi</a></p>