title: html5 required validator not working with input type=button
body: <p>Here is my html code</p>
  
  <pre><code>&lt;form id="form1" runat="server"&gt;
  &lt;input id="q" required /&gt;
  &lt;input id="btn" type="submit" value="Search"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>I have used html5 required field validators, it works but with a post back.
  so  modified the code as follows to avoid postback</p>
  
  <pre><code>&lt;form id="form1" runat="server"&gt;
  &lt;input id="q" required /&gt;
  &lt;input id="btn" type="button" value="Search"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>But the required validator doesn't work</p>