html - 键盘可访问的下拉菜单不遍历子菜单

Question

我需要一些帮助来解决我的导航问题。当使用选项卡按钮使列表项成为焦点时，我可以获得导航以显示下拉菜单，但我无法让选项卡遍历下拉菜单(子菜单)，它只是跳转到下一个列表项标签.

我试过 jQuery 但没有成功，现在我只是尝试使用 html、css 和 tabindex，但仍然没有成功。

HTML

    <nav aria-label="Main menu" id="globalNav" >
      <ul>
       <li class="dropdown" tabindex="0" ><a href="#"><span itemprop="name">Welcome</span></a>
        <ul class="sub-menu">
         <li role="menuitem"><a href="#">Visitor</a></li>
         <li role="menuitem"><a href="#">Aid</a></li>
         <li role="menuitem"><a href="#">Payments</a></li>
       </ul>
      </li>
     <li class="dropdown" tabindex="0"><a href="#"><span itemprop="name">Sports</span></a>
       <ul class="sub-menu">
        <li role="menuitem"><a href="#">Basketball</a></li>
        <li role="menuitem"><a href="#">Football</a></li>
        <li role="menuitem"><a href="#">Soccer</a></li>
      </ul>
     </li>
    </ul>
  </nav>

CSS

    #globalNav {
     width: 100%;
     border-bottom: 3px solid rgba(74, 61, 48, 0.3);
     padding: 0.54rem 0;
     margin-top: 30px;
     z-index: 10;
   }
   #globalNav ul {    
     list-style: none;
     display: table;
     margin: 0 auto;
     font-size: 1rem;
     text-transform: uppercase;
   }
   #globalNav ul li.dropdown {
     display: table-cell;
     padding: 0 10px;
     border-left: 1px solid #EEE;
     text-align: center;
   }

  #globalNav ul li.dropdown a{
    color: #4A3D30;
    display: inline-block;
    position: relative;
   }
    #globalNav ul li.dropdown a:hover,
    #globalNav ul li.dropdown a:focus,
    #globalNav ul li.dropdown a:active{
       color:#666;
    }

    #globalNav ul li.dropdown a.active:after{
      width: 100%;
      background: #990000;
    }

    #globalNav ul li.dropdown a:after{
      content: "";
      display: block;
      margin: auto;
      height: 2px;
      width: 0;
      background-color: transparent;
   }
  /*Children GlobalNav*/
   #globalNav ul li.dropdown a ul.sub-menu {
   }

    #globalNav ul li.dropdown  ul.sub-menu {
      position: absolute;
      display: none;
      z-index: 100;
      text-transform: none;
      min-width: 256px;
      max-width: 256px;
   }

    #globalNav ul li.dropdown:hover  ul.sub-menu,
    #globalNav ul li.dropdown:focus ul.sub-menu,
    #globalNav ul li.dropdown:active ul.sub-menu{
     display: block;
     background-color: #dcd8d6;
     color: #4a3d30;
   }
    #globalNav ul li.dropdown ul.sub-menu:hover,
    #globalNav ul li.dropdown ul.sub-menu:focus,
    #globalNav ul li.dropdown ul.sub-menu:active {
      background-color: #3f79c1;
    }

   #globalNav ul li.dropdown ul.sub-menu li a {
    padding: 8px;
   }

这是我的代码笔 http://codepen.io/nicban/pen/vmEEPr

我觉得我错过了一些明显的东西

Answer 1

我使用一些脚本向具有焦点的元素添加一个类，然后遍历 DOM 将其添加到祖先，以便我可以显示它们。当焦点改变时，我也会删除该类。

自从我审查它以删除/调整任何愚蠢的部分以来已经有一段时间了。

您遇到的部分问题是您使用的是 display: none，这意味着键盘永远找不到它。如果您使用屏幕外技术，则用户可以通过 Tab 进入控件。

此外，请删除整个 role="menuitem" 以及 tabindex="0"。前者意味着您不支持的交互(例如箭头键)，后者会创建额外的制表位，这些制表位不会正确地向屏幕阅读器宣布自己。

    // Get the nav by id
    var pNav = document.getElementById("globalNav");

    function unClassy(){
      try {
        // Remove the focus class
        pNav.classList.remove("focus");
        // Remove the focus class from all its descendents
        pNavDesc = pNav.getElementsByTagName('*');
        for( var i = 0; i<pNavDesc.length; i++){
          pNavDesc[i].removeAttribute("class");
        }
      } catch (e) {
        console.log(e);
      } 
    }

    /* For any clicks, clear the focus class from the nav and all its descendants, essentially closing the menu when a user clicks/taps outside of it. */
    document.documentElement.onclick=function() {
      try {
        unClassy();
      } catch (e) {
        console.log(e);
      }
    }

    /* Manipulate focus classes in navigation. */
    function classy(){
      try {
        unClassy();
        // Add the focus class to items that have focus
        // Get the element that currently has focus
        var focusedElement = document.activeElement;
        // If that element is the primary nav, add the class
        if (focusedElement.id == pNav.id){
          // Add the focus class
          pNav.classList.add("focus");
        }
        // If nav contains the focused element, add the class
        if (pNav.contains(focusedElement)){
          focusedElement.classList.add("focus");
          el = focusedElement;
          while (el.parentNode) {
            el.classList.add("focus");
            el = el.parentNode;
          }
        }
      } catch (e) {
        console.log(e);
      }
    }

    /* Delay the assigning of classes to give the :focus a chance to catch up. There has to be a better way for this. */
    document.documentElement.addEventListener("keydown", delayClassy, false);
    function delayClassy(){
      try {
        setTimeout(classy, 200);
      } catch (e) {
        console.log(e);
      }
    }