bootstrap 表单控件大小

<form role="form"> <div class="form-group"> <input class="form-control input-lg" type="text" placeholder=".input-lg"> </div> <div class="form-group"> <input class="form-control" type="text" placeholder="默认输入"> </div> <div class="form-group"> <input class="form-control input-sm" type="text" placeholder=".input-sm"> </div> <div class="form-group"></div> <div class="form-group"> <select class="form-control input-lg"> <option value="">.input-lg</option> </select> </div> <div class="form-group"> <select class="form-control"> <option value="">默认选择</option> </select> </div> <div class="form-group"> <select class="form-control input-sm"> <option value="">.input-sm</option> </select> </div> <div class="row"> <div class="col-lg-2"> <input type="text" class="form-control" placeholder=".col-lg-2"> </div> <div class="col-lg-3"> <input type="text" class="form-control" placeholder=".col-lg-3"> </div> <div class="col-lg-4"> <input type="text" class="form-control" placeholder=".col-lg-4"> </div> </div> </form>