Bootstrap .has-warning类
具有警告类可让您设置输入警告。
您可以尝试运行以下代码来实现has-warning类：
示例
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Example</title>
<link href = "/bootstrap/css/bootstrap.min.css" rel = "stylesheet">
<script src = "/scripts/jquery.min.js"></script>
<script src = "/bootstrap/js/bootstrap.min.js"></script>
</head>
<body>
<form class = "form-horizontal" role = "form">
<div class = "form-group has-warning">
<label class = "col-sm-2 control-label" for = "inputWarning">
Input with warning
</label>
<div class = "col-sm-10">
<input type = "text" class = "form-control" id = "inputWarning">
</div>
</div>
</form>
</body>
</html>