aria-label
正常情况下,form表单的input组件都有对应的label.当input组件获取到焦点时,屏幕阅读器会读出相应的label里的文本。
<!doctype html> <html> <head> <meta charset = "utf-8"> <title>demo</title> <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="external nofollow" integrity="sha384-gn5384xqq1aowxa+058rxpxpg6fy4iwvtnh0e263xmfcjlsawiggfaw/dais6jxm" crossorigin="anonymous"> <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.slim.min.js" integrity="sha384-kj3o2dktikvyik3uenzmm7kckrr/re9/qpg6aazgjwfdmvna/gpgff93hxpg5kkn" crossorigin="anonymous"></script> <script src="https://cdn.bootcss.com/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-apnbgh9b+y1qktv3rn7w3mgpxhu9k/scqsap7huibx39j7fakfpskvxusvfa0b4q" crossorigin="anonymous"></script> <script src="https://cdn.bootcss.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-jzr6spejh4u02d8jot6vlehfe/jqgirrsqqxsffwpi1mquvdayjuar5+76pvcmyl" crossorigin="anonymous"></script> <style type="text/css"> body{padding: 20px;} </style> </head> <body> <form role = "form"> <div class="form-group col-lg-3 form-horizontal"> <label for = "idcard" class="control-label col-lg-5">身份证号:</label> <div class="col-lg-7"> <input type = "text" id = "idcard" class="form-control"> </div> </div> </form> </body> </html>
但是如果我们没有给输入框设置label时,当其获得焦点时,屏幕阅读器会读出aria-label属性的值,aria-label不会在视觉上呈现效果。
<body> <form role = "form"> <div class="form-group col-lg-3 form-horizontal"> <div class="col-lg-7"> <input type = "text" id = "idcard" class="form-control" aria-label = "身份证号"> </div> </div> </form> </body> aria-labelledby <body> <div class="dropdown"> <button type="button" class="btn dropdown-toggle" id="dropdownmenu1" data-toggle="dropdown"> 选择您的职位 <span class="caret"></span> </button> <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownmenu1"> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" >测试工程师</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" >开发工程师</a> </li> <li role="presentation"> <a role="menuitem" tabindex="-1" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" >销售工程师</a> </li> </ul> </div> </body>
注:
如果一个元素同时有aria-labelledby和aria-label,读屏软件会优先读出aria-labelledby的内容
总结
以上所述是小编给大家介绍的bootstrap的aria-label和aria-labelledby属性实例详解,希望对大家有所帮助
如对本文有疑问, 点击进行留言回复!!
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