title: Wordpress: Add custom ID to final li in wp_nav_menu
body: <p>I'm using three primary navs in my theme and I'm attempting to place a final link to the menu with a custom ID across all primary navs.</p>
  
  <p>This is what I'm going for:</p>
  
  <pre><code>&lt;nav id="menu" role="navigation" class="menu-primary"&gt;
    &lt;ul id="nav" class="menu"&gt;
      &lt;li id="menu-item-418" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-418"&gt;&lt;a href="#"&gt;About&lt;/a&gt;&lt;/li&gt;
      &lt;li id="menu-item-474" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-474"&gt;&lt;a href="#"&gt;Work&lt;/a&gt;&lt;/li&gt;
      &lt;li id="menu-item-463" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-463"&gt;&lt;a href="#"&gt;Blog&lt;/a&gt;&lt;/li&gt;
      &lt;li id="menu-item-416" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-416"&gt;&lt;a href="#"&gt;Contact&lt;/a&gt;&lt;/li&gt;
      &lt;li id="back" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-491"&gt;&lt;href="#header"&gt;back&lt;/a&gt;&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/nav&gt;
  </code></pre>
  
  <p>As you can see, the final li has an ID of 'back'. Any idea how I can accomplish this without the use of js? I can see how I can change classes, but not ID's. I'm doing this for CSS purposes.</p>
  
  <p>Any help will be greatly appreciated!</p>