Applying border-right to all elements except the last one

Question

I have Wordpress pages looking like this: Page 1 | Page 2 | Page 3 |

I don't want a border-right on Page 3. How can I delete it?

.primary-navigation {
  float: left;
}
.primary-navigation a {
  margin-top: 16px;
  margin-bottom: 12px;
  padding-left: 23px;
  padding-right: 23px;
  border-right: 1px dotted #7b7f82;
  position: relative;
  line-height: 1;
}
.primary-navigation .menu-item-has-children a {
  padding-right: 35px
}

<div id="primary-navigation" class="primary-navigation" role="navigation" itemscope itemtype="http://schema.org/SiteNavigationElement">
  <nav id="navigation" class="navigation clearfix mobile-menu-wrapper">
    <a href="#" id="pull" class="toggle-mobile-menu">
      <?php _e( 'Menu'); ?>
    </a>
    <?php if (has_nav_menu( 'primary-menu')) { ?>
    <?php wp_nav_menu(array( 'theme_location'=>'primary-menu', 'menu_class' => 'menu clearfix', 'menu_id' => 'menu-primary-menu', 'container' => '', 'walker' => new mts_menu_walker)); ?>
    <?php } else { ?>
    <ul class="menu clearfix" id="menu-primary-menu">
      <?php wp_list_pages( 'title_li='); ?>
    </ul>
    <?php } ?>
  </nav>
</div>

Answer 1

Use the :last-child pseudo-class to set border-right: none; on the last <a> in your .primary-navigation.

.primary-navigation a {
    margin-top: 16px;
    margin-bottom: 12px;
    padding-left: 23px;
    padding-right: 23px;
    border-right: 1px dotted #7b7f82;
    position: relative;
    line-height: 1;
}

.primary-navigation li:last-child a {
    border-right: none;
}

More on the :last-child pseudo-class on MDN.