title: onClick to get the ID of the clicked button
body: <p>How do find the id of the button which is being clicked?</p>
  
  <pre><code>&lt;button id="1" onClick="reply_click()"&gt;&lt;/button&gt;
  &lt;button id="2" onClick="reply_click()"&gt;&lt;/button&gt;
  &lt;button id="3" onClick="reply_click()"&gt;&lt;/button&gt;
  
  function reply_click()
  {
  }
  </code></pre>