jquery下拉框事件

$(document).ready(function(){
var arrData = {
"工厂1":{"品牌1":["型号1","型号2"],"品牌2":["型号3","型号4"] },
"工厂2":{"品牌3":["型号a","型号b"],"品牌4":["型号c","型号d"] }
};
$.each(arrData,function(index,elem){
$("#cs").children(":last").after("<option>"+ index+ "</option>")
});
$("#cs").change(function(){
var selected = $("#cs option:selected").text();
$("#pp").children().remove();
$("#xh").children().remove();
$("#pp").append("<option>" + "请选择" + "</option>")
$("#xh").append("<option>" + "请选择" + "</option>")
$.each(arrData[selected],function(key,value){
$("#pp").append("<option>" + key + "</option>")
})
});
$("#pp").change(function(){
var selected = $("#cs option:selected").text();
$("#xh").children().remove();
$("#xh").append("<option>" + "请选择" + "</option>")
var temp = $("#pp").children(":selected").text();
$.each(arrData[selected][temp],function(key,value){
$("#xh").append("<option>" + value + "</option>")
})
})
})