Ajax动态拼接下拉框实现联动效果

Ajax实现下拉框联动效果，动态拼接下拉框选项，实现从数据库中加载数据

<div class="form-group">
<label>车系品牌：</label>
<form:select id="brand" path="brand" class="form-control input-sm">
<form:option value="" label="请选择"/>
<form:options items="${brandList}" htmlEscape="false"/></form:select>
<label>车系名称：</label>
<form:select id="seriesName" path="seriesName" class="form-control input-sm">
<form:option value="" label="请选择"/>
</form:select>
</div>

<script type="text/javascript">$(document).ready(function() {if($("#brand").val()!=null && $("#brand").val()!=""){selectC();}$("#brand").change(function(){selectC();}); function selectC(){var name = $("#seriesName");   var brand=$("#brand").val();$.ajax({  url: "${ctx}/product/carSeries/search?brand="+brand,type:"post",dataType:"json",success: function(data){ var optionstring = "";  for (var i in data) {  var jsonObj =data[i];  optionstring += "<option value=\""  + jsonObj + "\">" + jsonObj + "</option>";  } $("#seriesName").html("<option value=''  >请选择</option>"+ optionstring); },});   } });</script>