闲话少叙，代码如下：
<!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link href="../css/bootstrap.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="../js/jquery172.min.js"></script>
<script type="text/javascript" src="../js/bootstrap.min.js"></script>
<title>查询演示</title>
</head>
<body>
<form name="form1" class="form-inline" id="form1" onsubmit='return searchFiles()'>
<div class="input-group">
<div class="input-group-btn">
<button type="button" class="btn btn-default btn-sm dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<span id="searchTitle" >查标题</span><span class="caret"></span>
</button>
<ul class="dropdown-menu">
<li><a href="javascript:searchWhat(1)">查标题</a></li>
<li><a href="javascript:searchWhat(2)">查作者</a></li>
</ul>
</div>
<input type="text" class="form-control input-sm" placeholder="" id="searchStr" value="">
<span class="input-group-btn">
<div class="btn btn-success btn-sm" onclick="searchFiles()" type="submit"><span class="glyphicon glyphicon-search" aria-hidden="true"></span>查找</div>
</span>
</div>
</form>
</body>
</html>效果：
