<?xml version="1.0" encoding="utf-8"?><area Country="China"> <province ID="1" provinceID="110000" province="北京市">  <City CityID="110100" City="市轄區">   <Piecearea PieceareaID="110101" Piecearea="東城區" />   <Piecearea PieceareaID="110102" Piecearea="西城區" />   <Piecearea PieceareaID="110103" Piecearea="崇文區" />   <Piecearea PieceareaID="110104" Piecearea="宣武區" />   <Piecearea PieceareaID="110105" Piecearea="朝陽區" />   <Piecearea PieceareaID="110106" Piecearea="豐臺區" />   <Piecearea PieceareaID="110107" Piecearea="石景山區" />   <Piecearea PieceareaID="110108" Piecearea="海淀區" />   <Piecearea PieceareaID="110109" Piecearea="門頭溝區" />   <Piecearea PieceareaID="110111" Piecearea="房山區" />   <Piecearea PieceareaID="110112" Piecearea="通州區" />   <Piecearea PieceareaID="110113" Piecearea="順義區" />   <Piecearea PieceareaID="110114" Piecearea="昌平區" />   <Piecearea PieceareaID="110115" Piecearea="大興區" />   <Piecearea PieceareaID="110116" Piecearea="懷柔區" />   <Piecearea PieceareaID="110117" Piecearea="平谷區" />  </City><province>

<h2>地區三級聯動菜單</h2>  省:<select id="province" onchange="showcity()"><option value="0">-請選擇-</option></select>  市:<select id="city" onchange="showdistrict()"><option value="0">-請選擇-</option></select>  地區:<select id="district"><option value="0">-請選擇-</option></select>

//聲明一個全局變量，用于存儲第一次請求的xml信息,避免后續多次頻繁請求xml    var xmldom =null;    //獲取并顯示省份信息    function showprovince(){      //使用ajax去服務器獲得xml文件里面的省份信息      $.ajax({        url:'./ChinaArea.xml',        //data:        dataType:'xml',//相當于調用responseXML        type:'get',        success:function(msg){          //將返回的xml信息賦予xmldom          xmldom = msg;          //獲得province 元素節點對象          var prov = $(msg).find('province');          //遍歷省份信息          prov.each(function(k,v){            var nm = $(this).attr('province');            var id = $(this).attr('provinceID');            //追加到指定的節點            $('#province').append("<option value="+id+">"+nm+"</option>");          });        }      });    }    //網頁加載顯示省份信息      $(function(){      showprovince();    });    function showcity(){      //獲取 省份 的id      var pid = $('#province option:selected').val();      //根據xmldom信息 找到指定的省份節點      var xml_province = $(xmldom).find('province[provinceID='+pid+']');      // 獲取對應所有縣市節點      var city = $(xml_province).find('City');      //在遍歷追加前，先清空此前已經顯示的信息      $('#city').empty();      $('#city').append('<option value="0">-請選擇-</option>');      //遍歷追加縣市      city.each(function(k,v){        var nm = $(this).attr('City');        var id = $(this).attr('CityID');        $('#city').append('<option value='+id+'>'+nm+'</option>');      });    }    //以下函數的邏輯與showcity()的邏輯一致    function showdistrict(){      //獲取 縣市 的id      var cid = $('#city option:selected').val();      //根據xmldom信息 找到指定的縣市節點      var xml_city = $(xmldom).find('City[CityID='+cid+']');      // 獲取對應所有地區節點      var district = $(xml_city).find('Piecearea');      $('#district').empty();      $('#district').append('<option value="0">-請選擇-</option>');      district.each(function(k,v){        var nm = $(this).attr('Piecearea');        var id = $(this).attr('PieceareaID');        $('#district').append('<option value='+id+'>'+nm+'</option>');      });    }