当我在jQuery中调用其内容时，div标签未显示

Question

html代码：<div class="col-md-12">                      <span>Select Payment Option</span> <select class="form-control" name="select1" id="select1"  onchange="fun_showtextbox()"> <option value="x">Cash</option>  <option value="y">Cheque</option>  <option value="z">Mobile Money</option> </select>  </div>  <div class ="row" style="display:none;" id="mobileno_textbox">  <div class="col-md-12">  <div class="form-group label-floating is-empty is-focused">    <label class ="control-label">Cash</label>  <input type="text" name="select" "id="select"class="form-   control"placeholder="number"> </div> </div>                                                                    </div> <div class ="row">   <div class="col-md-12">  <div class="form-group label-floating is-empty is-focused">  <label class ="control-label">Amount: </label>   <input type="text" name="select" "id="select"class="form-control"   placeholder="amount">   </div>   </div>                                                                      </div>调用该函数后，div中的数字内容未显示。jQuery代码：function fun_showtextbox() {  var select_status=$('#select1').val(); /* select  from select box then show my text box */  if(select_status == "y")   {    $('#mobileno_textbox').show();// By using this id you can show your   content       }     else   {    $('#mobileno_textbox').hide();// otherwise hide     } }我不知道自己在做什么错，但是id =“ mobileno_textbox”的div内容没有显示？