这篇文章主要介绍了Bootstrap中aria-label和aria-labelledby属性有什么用，具有一定借鉴价值，感兴趣的朋友可以参考下，希望大家阅读完这篇文章之后大有收获，下面让小编带着大家一起了解一下。
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-JZR6Spejh5U02d8jOt6vLEHfe/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
感谢你能够认真阅读完这篇文章，希望小编分享的“Bootstrap中aria-label和aria-labelledby属性有什么用”这篇文章对大家有帮助，同时也希望大家多多支持亿速云，关注亿速云行业资讯频道，更多相关知识等着你来学习!
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