Boostrap Modal Drop Down隐藏在Modal后面

Question

我使用Bootstrap创建提交客户端信息的模式。但我发现Bootstrap模态下拉隐藏在模态后面。我搜索一些文件，但没有一个可以工作。我使用backbonejs来创建<span>，它会调用ajax从API获取所有的状态名称。但它应该显示一个下拉菜单。 下面是主要代码：

<div class="modal fade" id="clientinfoForm" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true"> 
<div class="modal-dialog modal-lg"> 
    <div class="modal-content"> 
     <div class="modal-header"> 
      <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button> 
      <h2 class="modal-title" id="myModalLabel">Client Info</h2> 
     </div> 
     <div class="modal-body"> 
      <form id="InfoRequestForm" class="responsive-form" method="POST"> 
      //The Problem Codes here, it is a input field to let client 
      //enter the state information and autocomplete through drop down menu 
     <div class="col-sm-8 col-xs-6"> 
      <label>State*</label> 
      <input name="state" id="state" type="text" class="large state" value="" /> 
      <span role="status" aria-live="polite" class="ui-helper-hidden-accessible">1 result is available, use up and down arrow keys to navigate.</span> 
      <input type="hidden" class="stateId" value="" /> 
      <input id="stateName" type="hidden" value="" /> 
          </div> 

“UI辅助隐藏可访问”是一类我创建：

.ui-helper-hidden-accessible { 
    border: 0; 
    clip: rect(0 0 0 0); 
    height: 1px; 
    margin: -1px; 
    overflow: hidden; 
    padding: 0; 
    position: absolute; 
    width: 1px; 
} 

感谢

Answer 1

一个Z指数添加到您的下拉。