Split-style button for "New" custom element
Those split-style buttons are just multiple regular buttons (.btn) next to each other, wrapped in a .btngroup div:



&lt;div class="btngroup submit"&gt;
  &lt;a class="btn submit" href="#"&gt;Button One&lt;/a&gt;
  &lt;a class="btn submit" href="#"&gt;Button Two&lt;/a&gt;
&lt;/div&gt;


If you want to make one of your buttons trigger a dropdown menu, give it the class .menubtn, and add your .menu div right after it.

&lt;div class="btngroup submit"&gt;
  &lt;a class="btn submit" href="#"&gt;Button One&lt;/a&gt;
  &lt;div class="btn menubtn submit" href="#"&gt;Menu Button&lt;/div&gt;
  &lt;div class="menu"&gt;
    &lt;ul&gt;
      &lt;li&gt;&lt;a href="#"&gt;Option One&lt;/a&gt;&lt;/li&gt;
      &lt;li&gt;&lt;a href="#"&gt;Option Two&lt;/a&gt;&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/div&gt;
&lt;/div&gt;


As long as this HTML is in the page’s initial HTML, Craft will automatically initialize the menu. If you’re adding it in JavaScript later on, you will need to initialize the menu yourself, by calling the menubtn() jQuery function on it:

$('#mycontainer .menubtn').menubtn();