当我专注于一个班级时，如何改变另一个班级的边界。？答案

【问题标题】：How to change the border of another class as i focus on one.?当我专注于一个班级时，如何改变另一个班级的边界。？
【发布时间】：2018-05-03 06:35:15
【问题描述】：

        <form class="navbar-form" >
            <div class="input-group">
              <input type="text" class="form-control search-form" placeholder="Search">
               <span class="input-group-btn"><button type="submit" class="btn btn-primary search-btn"><i class="fa fa-search"></i>
                </button></span>
            </div>
        </form>


.search-form {
border-radius: 30px 0px 0px 30px;
background-color: transparent;
border: 1px solid #ffffff;
border-right: 0px;
}
.search-btn {
border-radius: 0px 30px 30px 0px;
cursor:pointer;
background-color: transparent;
border: 1px solid #ffffff;
border-left: 0px;
}

当我专注于 .form-control 类时，如何使 .search-btn 的边框与 .form-control 相同？当专注于输入字段时，我想使输入字段和搜索按钮的边框颜色#fd9128。

【问题讨论】：

标签： html css

【解决方案1】：

使用下面的代码

.search-form {
border-radius: 30px 0px 0px 30px;
background-color: transparent;
border: 1px solid #ffffff;
border-right: 0px;
}
.search-btn {
border-radius: 0px 30px 30px 0px;
cursor:pointer;
background-color: transparent;
border: 1px solid #ffffff;
border-left: 0px;
  color:blue
}
.search-form:focus ~span .search-btn{
    border-color: #66afe9;
    outline: 0;
    -webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(102,175,233,.6);
    box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px rgba(102,175,233,.6);
}

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
  <title>JS Bin</title>
</head>
<body>
   <form class="navbar-form" >
     <div class="input-group">
       <input type="text" class="form-control search-form" placeholder="Search">
       <span class="input-group-btn"><button type="submit" class="btn btn-primary search-btn"><i class="fa fa-search">Submit</i>
         </button></span>
     </div>
  </form>
</body>
</html>

【讨论】：

【解决方案2】：

.search-form:focus .search-btn {
   border-radius: 30px 0px 0px 30px;     
   border: 1px solid #ffffff;
   border-right: 0px;
}

【讨论】：

【解决方案3】：

在按钮中添加此 CSS 以获得焦点

.search-form:focus + .input-group-btn button{
  background: transparent;
  border-color: #66afe9;
  color: #66afe9;
  box-shadow: inset 0 1px 1px rgba(0,0,0,.075),0 0 8px rgba(102,175,233,.6);
}

.search-form {
  border-radius: 30px 0px 0px 30px;
  background-color: transparent;
  border: 1px solid #ffffff;
  border-right: 0px;
}
.search-btn {
  border-radius: 0px 30px 30px 0px;
  cursor:pointer;
  background-color: transparent;
  border: 1px solid #ffffff;
  border-left: 0px;
}
.search-form:focus + .input-group-btn button{
  background: transparent;
  border-color: #66afe9;
  color: #66afe9;
  box-shadow: inset 0 1px 1px rgba(0,0,0,.075),0 0 8px rgba(102,175,233,.6);
}

<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" ></script>
<form class="navbar-form" >
    <div class="input-group">
      <input type="text" class="form-control search-form" placeholder="Search">
       <span class="input-group-btn"><button type="submit" class="btn btn-primary search-btn"><i class="fa fa-search"></i>
        </button></span>
    </div>
</form>

【讨论】：