//引入的包
<!-- bootstrap -->
<link rel="stylesheet" type="text/css" href="map/plug-in/scripts/bootstrap/bootstrap.min.css" rel="external nofollow" />
<link rel="stylesheet" type="text/css" href="map/plug-in/scripts/bootstrap/bootstrap-select.css" rel="external nofollow" />
<script type="text/javascript" src="map/plug-in/scripts/bootstrap/bootstrap.min.js"></script>
<script type="text/javascript" src="map/plug-in/scripts/bootstrap/bootstrap-select.js"></script>


//下拉框（代碼）
function getLayerLoad(tcId){
$.ajax({ 
url:layerSelUrl,
 dataType:'jsonp',
 data:'',
 jsonp:'callback',
 async:false,
 jsonpCallback:"success_jsonpCallback",
 success:function(data){
 $("#"+tcId).empty();
 $("#"+tcId).append("<option>---請選擇---</option>");
 $.each(data.bussinessTypes,function(i,o){
 var opt="";
 if(o.url){
 opt+='<option url='+o.url+'>'+i+'</option>';
 
 }else{
 opt+='<option url="">'+i+'</option>';
 }
 $("#"+tcId).append(opt);
 });
 $("#"+tcId).selectpicker('refresh');//動態(tài)加載
 },error:function(){
 }
});
}

<select class="selectpicker" id="selectpickers">
<option>---請選擇---</option>
</select>