js实现省市二级联动

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<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
        <style>
        <!--
        body         { font-size: 14px }
        -->
        </style>
       
        <script language="javascript" type="text/javascript">
        <!--
        var where = new Array(35);
        function comefrom(loca,locacity) { this.loca = loca; this.locacity = locacity; }
        where[0]= new comefrom("请选择省份名","请选择城市名");
        where[1] = new comefrom("北京","|东城|西城|崇文|宣武|朝阳|丰台|石景山|海淀|门头沟|房山|通州|顺义|昌平|大兴|平谷|怀柔|密云|延庆");
        where[2] = new comefrom("上海","|黄浦|卢湾|徐汇|长宁|静安|普陀|闸北|虹口|杨浦|闵行|宝山|嘉定|浦东|金山|松江|青浦|南汇|奉贤|崇明");
        where[3] = new comefrom("天津","|和平|东丽|河东|西青|河西|津南|南开|北辰|河北|武清|红挢|塘沽|汉沽|大港|宁河|静海|宝坻|蓟县");
        where[4] = new comefrom("重庆","|万州|涪陵|渝中|大渡口|江北|沙坪坝|九龙坡|南岸|北碚|万盛|双挢|渝北|巴南|黔江|长寿|綦江|潼南|铜梁|大足|荣昌|壁山|梁平|城口|丰都|垫江|武隆|忠县|开县|云阳|奉节|巫山|巫溪|石柱|秀山|酉阳|彭水|江津|合川|永川|南川");
        where[5] = new comefrom("河北","|石家庄|邯郸|邢台|保定|张家口|承德|廊坊|唐山|秦皇岛|沧州|衡水");
        where[6] = new comefrom("山西","|太原|大同|阳泉|长治|晋城|朔州|吕梁|忻州|晋中|临汾|运城");
        where[7] = new comefrom("内蒙古","|呼和浩特|包头|乌海|赤峰|呼伦贝尔盟|阿拉善盟|哲里木盟|兴安盟|乌兰察布盟|锡林郭勒盟|巴彦淖尔盟|伊克昭盟");
        where[8] = new comefrom("辽宁","|沈阳|大连|鞍山|抚顺|本溪|丹东|锦州|营口|阜新|辽阳|盘锦|铁岭|朝阳|葫芦岛");
        where[9] = new comefrom("吉林","|长春|吉林|四平|辽源|通化|白山|松原|白城|延边");
        where[10] = new comefrom("黑龙江","|哈尔滨|齐齐哈尔|牡丹江|佳木斯|大庆|绥化|鹤岗|鸡西|黑河|双鸭山|伊春|七台河|大兴安岭");
        where[11] = new comefrom("江苏","|南京|镇江|苏州|南通|扬州|盐城|徐州|连云港|常州|无锡|宿迁|泰州|淮安");
        where[12] = new comefrom("浙江","|杭州|宁波|温州|嘉兴|湖州|绍兴|金华|衢州|舟山|台州|丽水");
        where[13] = new comefrom("安徽","|合肥|芜湖|蚌埠|马鞍山|淮北|铜陵|安庆|黄山|滁州|宿州|池州|淮南|巢湖|阜阳|六安|宣城|亳州");
        where[14] = new comefrom("福建","|福州|厦门|莆田|三明|泉州|漳州|南平|龙岩|宁德");
        where[15] = new comefrom("江西","|南昌市|景德镇|九江|鹰潭|萍乡|新馀|赣州|吉安|宜春|抚州|上饶");
        where[16] = new comefrom("山东","|济南|青岛|淄博|枣庄|东营|烟台|潍坊|济宁|泰安|威海|日照|莱芜|临沂|德州|聊城|滨州|菏泽");
        where[17] = new comefrom("河南","|郑州|开封|洛阳|平顶山|安阳|鹤壁|新乡|焦作|濮阳|许昌|漯河|三门峡|南阳|商丘|信阳|周口|驻马店|济源");
        where[18] = new comefrom("湖北","|武汉|宜昌|荆州|襄樊|黄石|荆门|黄冈|十堰|恩施|潜江|天门|仙桃|随州|咸宁|孝感|鄂州");
        where[19] = new comefrom("湖南","|长沙|常德|株洲|湘潭|衡阳|岳阳|邵阳|益阳|娄底|怀化|郴州|永州|湘西|张家界");
        where[20] = new comefrom("广东","|广州|深圳|珠海|汕头|东莞|中山|佛山|韶关|江门|湛江|茂名|肇庆|惠州|梅州|汕尾|河源|阳江|清远|潮州|揭阳|云浮");
        where[21] = new comefrom("广西","|南宁|柳州|桂林|梧州|北海|防城港|钦州|贵港|玉林|南宁地区|柳州地区|贺州|百色|河池");
        where[22] = new comefrom("海南","|海口|三亚");
        where[23] = new comefrom("四川","|成都|绵阳|德阳|自贡|攀枝花|广元|内江|乐山|南充|宜宾|广安|达川|雅安|眉山|甘孜|凉山|泸州");
        where[24] = new comefrom("贵州","|贵阳|六盘水|遵义|安顺|铜仁|黔西南|毕节|黔东南|黔南");
        where[25] = new comefrom("云南","|昆明|大理|曲靖|玉溪|昭通|楚雄|红河|文山|思茅|西双版纳|保山|德宏|丽江|怒江|迪庆|临沧");
        where[26] = new comefrom("西藏","|拉萨|日喀则|山南|林芝|昌都|阿里|那曲");
        where[27] = new comefrom("陕西","|西安|宝鸡|咸阳|铜川|渭南|延安|榆林|汉中|安康|商洛");
        where[28] = new comefrom("甘肃","|兰州|嘉峪关|金昌|白银|天水|酒泉|张掖|武威|定西|陇南|平凉|庆阳|临夏|甘南");
        where[29] = new comefrom("宁夏","|银川|石嘴山|吴忠|固原");
        where[30] = new comefrom("青海","|西宁|海东|海南|海北|黄南|玉树|果洛|海西");
        where[31] = new comefrom("新疆","|乌鲁木齐|石河子|克拉玛依|伊犁|巴音郭勒|昌吉|克孜勒苏柯尔克孜|博尔塔拉|吐鲁番|哈密|喀什|和田|阿克苏");
        where[32] = new comefrom("香港","");
        where[33] = new comefrom("澳门","");
        where[34] = new comefrom("台湾","|台北|高雄|台中|台南|屏东|南投|云林|新竹|彰化|苗栗|嘉义|花莲|桃园|宜兰|基隆|台东|金门|马祖|澎湖");
        where[35] = new comefrom("其它","|北美洲|南美洲|亚洲|非洲|欧洲|大洋洲");
        function select() {
        with(document.addfrm.province) { var loca2 = options[selectedIndex].value; }
        for(i = 0;i < where.length;i ++) {
        if (where[i].loca == loca2) {
        loca3 = (where[i].locacity).split("|");
        for(j = 0;j < loca3.length;j++) { with(document.addfrm.city) { length = loca3.length; options[j].text = loca3[j]; options[j].value = loca3[j]; var loca4=options[selectedIndex].value;}}
        break;
        }}
        document.addfrm.newlocation.value=loca2+loca4;
        }
        function init() {
        with(document.addfrm.province) {
        length = where.length;
        for(k=0;k<where.length;k++) { options[k].text = where[k].loca; options[k].value = where[k].loca; }
        options[selectedIndex].text = where[0].loca; options[selectedIndex].value = where[0].loca;
        }
        with(document.addfrm.city) {
        loca3 = (where[0].locacity).split("|");
        length = loca3.length;
        for(l=0;l<length;l++) { options[l].text = loca3[l]; options[l].value = loca3[l]; }
        options[selectedIndex].text = loca3[0]; options[selectedIndex].value = loca3[0];
        }}
        -->
        </script>
</head>
<body onload="init()">
请输入您所在国家的具体地方。此项可选
<form onload="" action="" method="post" name="addfrm" >
  <div >
        省份<select name="province" onchange= "select()"></select>
      　城市<select name="city" onchange = "select()"></select>

        我在<input style="width:100px;font-weight: bold" type="text" name="newlocation" maxlength="12" size="12" />　不能超过12个字符（6个汉字）

       <input type="hidden"  name="newlocation2" />
 </div>
</form>
</body>
</html>