Inputs will only be fully styled if their type is properly declared.
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
</head><!--from w w w. j av a2 s .com-->
<body style='margin:20px;'>
<form class="form-horizontal">
<input type="text" class="form-control" placeholder="Text input">
</form>
</body>
</html>