title: Forbid letters in number field in html5
body: <p>I want to prevent the user from entering non-numeric characters in a textfield for telephone number in HTML5.  I tried this, but it doesn't forbid non-numeric characters:</p>
  
  <pre><code>&lt;input type="tel"  name="usrtel"&gt;&lt;br&gt;
  </code></pre>
  
  <p>I tried using <code>type=number</code> as well, but that gives me a up and a down arrow to increase or decrease the value, which is not useful for telephone numbers.  How can I accomplish this?</p>