搜索框

<div class="col-md-3 input-group hidden-xs" style="margin-top:30px">
    <input type="text" class="form-control" style="position:relative;top:1px;" placeholder="请您输入关键字……">
    <span class="glyphicon glyphicon-search input-group-addon" aria-hidden="true"></span>
</div>