title: how to use switch case(range of number) in jquery?
body: <p>i try to user switch (range of number)
  but it seems not work?
  can you help me check it where is the problem?</p>
  
  <p><a href="http://goo.gl/mK5WJK" rel="nofollow"><strong>JSFIDDLE</strong></a></p>
  
  <pre><code>case (tot&gt;10 &amp;&amp; tot&lt;110):
           $total.html(tot);
           $risk.html('小');
  break;
  
  case (tot&gt;110 &amp;&amp; tot&lt;310):
           $total.html(tot);
           $risk.html('大');
  </code></pre>