用ajax实现一个省市的级联关系！

Java代码







<!-- 主菜单 -->
<s:select name="first" list="%{province}" listKey="id" listValue="name"

onchange="javascript:showCity(this.value)" headerKey="-1" headerValue="请选择省份" theme="simple">

</s:select>

<!-- ajax-->
function showCity(provinceid){
$.ajax({
type : "POST",
url : "/Classifiction/showCityAjax.htm?provinceid="+provinceid,

dataType : "json",

success : function(obj) {
//清空下拉列表

$("#second").empty();

//把action中的字符串赋给新的下拉列表

$("#second").append(obj.secondMenu);

}
});
}

//<!-- action 部分代码-->
StringBuffer sBuffer = new StringBuffer();

if(onecai !=null && onecai.size() >
0){
for (SysHelpClassification helpClassification : onecai) {

sBuffer.append("<option value='" + helpClassification.getId() +
"'>" + helpClassification.getName() +
"</option>");
}
}
//secondMenu是传给副菜单下拉列表的
secondMenu = sBuffer.toString();

<!-- 副菜单 -->
<span id="secondMenu">
<select id="second" name="second">

<option value="">请选择市</option>

</select>
</span>