Link: Click here for a button!

Display button here: 


Code:
  <a href="javascript:void(0);"
        onclick="goYtSubscribeButton('GoogleDevelopers')">Click here for a button!</a>
  Display button here: <div id="yt-button-container-go"></div>
  <script>
    function goYtSubscribeButton() {
      // ID of element containing <div class="g-ytsubscribe"> element(s)
      // The container element already contains the button elements when this
      // function is called.
      var containerId = "sample-container";
      gapi.ytsubscribe.go(containerId);
    }
  </script>

  <b>Link</b>
  <a href="javascript:void(0);"
        onclick="goYtSubscribeButton('GoogleDevelopers')">Click here for a button</a>

  <b>Display button here:</b>
  <div id="yt-button-container-go" style="display-inline"></div>