this places the one click button in a zendesk custom widget that opens the Zendesk dropbox

javascript-widget-zenbox.js

</script>
<script type="text/javascript" src="//asset0.zendesk.com/external/zenbox/v2.1/zenbox.js"></script>
<style type="text/css" media="screen, projection">
  @import url(//asset0.zendesk.com/external/zenbox/v2.1/zenbox.css);
</style>
<script type="text/javascript">
  if (typeof(Zenbox) !== "undefined") {
    Zenbox.init({
      dropboxID:   "43",
      url:         "http://your.zendesk.com",
      tabID:       "questions",
      tabColor:    "#9060C1",
      tag: "dropbox_2",
      hide_tab: true,
      tabPosition: "Right"
    });
  }

zendesk-dropbox-button.html

<form>
<input type="button" value="zenbox" onClick="script: Zenbox.show(); return false;" />
</form>