今天测试了$.ajax()方法：

   $("a").click(function(){
        $.ajax({
           url:"MyJsp.jsp",
           type:"GET",
           success:function(msg){
           $("body").append(msg);
         }

参数url是目标地址源，type:是请求提交类型，success:function是回调函数，这个方法可以把jsp页面或者html页面直接当做msg传过来添加到body标签之后！

还有个

$.get("test.cgi", { name: "John", time: "2pm" },  function(data){    alert("Data Loaded: " + data);  });和

$.post("test.cgi", { name: "John", time: "2pm" },  function(data){    alert("Data Loaded: " + data);  });
方法，这里除了提交方式不一样，其他都一样：
url:为发送请求地址。
data (可选)：待发送 Key/value 参数。
callback (可选):发送成功时回调函数。
type (可选):返回内容格式，xml, html, script, json, text, _default。
如：$.get("index.jsp", { name: "John",age:"22" },
function(data){
alert( data);
  });

还有个jQuery.getJSON(url, [data], [callback])方法
测试方法是从json里面读取各个省份和省份下的城市加载到两个select标签里
citys.json文件里的数据为：
[{"name":"北京","cities":["西城","东城","崇文","宣武","朝阳","海淀","丰台","石景山","门头沟","房山","通州","顺义","大兴","昌平","平谷","怀柔","密云","延庆"]},{"name":"天津","cities":["青羊","河东","河西","南开","河北","红桥","塘沽","汉沽","大港","东丽","西青","北辰","津南","武清","宝坻","静海","宁河","蓟县","开发区"]},{"name":"河北","cities":["石家庄","秦皇岛","廊坊","保定","邯郸","唐山","邢台","衡水","张家口","承德","沧州","衡水"]},{"name":"山西","cities":["太原","大同","长治","晋中","阳泉","朔州","运城","临汾"]},{"name":"内蒙古","cities":["呼和浩特","赤峰","通辽","锡林郭勒","兴安"]},{"name":"辽宁","cities":["大连","沈阳","鞍山","抚顺","营口","锦州","丹东","朝阳","辽阳","阜新","铁岭","盘锦","本溪","葫芦岛"]},{"name":"吉林","cities":["长春","吉林","四平","辽源","通化","延吉","白城","辽源","松原","临江","珲春"]},{"name":"黑龙江","cities":["哈尔滨","齐齐哈尔","大庆","牡丹江","鹤岗","佳木斯","绥化"]},{"name":"上海","cities":["浦东","杨浦","徐汇","静安","卢湾","黄浦","普陀","闸北","虹口","长宁","宝山","闵行","嘉定","金山","松江","青浦","崇明","奉贤","南汇"]},{"name":"江苏","cities":["南京","苏州","无锡","常州","扬州","徐州","南通","镇江","泰州","淮安","连云港","宿迁","盐城","淮阴","沐阳","张家港"]},{"name":"浙江","cities":["杭州","金华","宁波","温州","嘉兴","绍兴","丽水","湖州","台州","舟山","衢州"]},{"name":"安徽","cities":["合肥","马鞍山","蚌埠","黄山","芜湖","淮南","铜陵","阜阳","宣城","安庆"]},{"name":"福建","cities":["福州","厦门","泉州","漳州","南平","龙岩","莆田","三明","宁德"]},{"name":"江西","cities":["南昌","景德镇","上饶","萍乡","九江","吉安","宜春","鹰潭","新余","赣州"]},{"name":"山东","cities":["青岛","济南","淄博","烟台","泰安","临沂","日照","德州","威海","东营","荷泽","济宁","潍坊","枣庄","聊城"]},{"name":"河南","cities":["郑州","洛阳","开封","平顶山","濮阳","安阳","许昌","南阳","信阳","周口","新乡","焦作","三门峡","商丘"]},{"name":"湖北","cities":["武汉","襄樊","孝感","十堰","荆州","黄石","宜昌","黄冈","恩施","鄂州","江汉","随枣","荆沙","咸宁"]},{"name":"湖南","cities":["长沙","湘潭","岳阳","株洲","怀化","永州","益阳","张家界","常德","衡阳","湘西","邵阳","娄底","郴州"]},{"name":"广东","cities":["广州","深圳","东莞","佛山","珠海","汕头","韶关","江门","梅州","揭阳","中山","河源","惠州","茂名","湛江","阳江","潮州","云浮","汕尾","潮阳","肇庆","顺德","清远"]},{"name":"广西","cities":["南宁","桂林","柳州","梧州","来宾","贵港","玉林","贺州"]},{"name":"海南","cities":["海口","三亚"]},{"name":"重庆","cities":["渝中","大渡口","江北","沙坪坝","九龙坡","南岸","北碚","万盛","双桥","渝北","巴南","万州","涪陵","黔江","长寿"]},{"name":"四川","cities":["成都","达州","南充","乐山","绵阳","德阳","内江","遂宁","宜宾","巴中","自贡","康定","攀枝花"]},{"name":"贵州","cities":["贵阳","遵义","安顺","黔西南","都匀"]},{"name":"云南","cities":["昆明","丽江","昭通","玉溪","临沧","文山","红河","楚雄","大理"]},{"name":"西藏","cities":["拉萨","林芝","日喀则","昌都"]},{"name":"陕西","cities":["西安","咸阳","延安","汉中","榆林","商南","略阳","宜君","麟游","白河"]},{"name":"甘肃","cities":["兰州","金昌","天水","武威","张掖","平凉","酒泉"]},{"name":"青海","cities":["黄南","海南","西宁","海东","海西","海北","果洛","玉树"]},{"name":"宁夏","cities":["银川","吴忠"]},{"name":"新疆","cities":["乌鲁木齐","哈密","喀什","巴音郭楞","昌吉","伊犁","阿勒泰","克拉玛依","博尔塔拉"]},{"name":"香港","cities":["中西区","湾仔区","东区","南区","九龙-油尖旺区","九龙-深水埗区","九龙-九龙城区","九龙-黄大仙区","九龙-观塘区","新界-北区","新界-大埔区","新界-沙田区","新界-西贡区","新界-荃湾区","新界-屯门区","新界-元朗区","新界-葵青区","新界-离岛区"]},{"name":"澳门","cities":["花地玛堂区","圣安多尼堂区","大堂区","望德堂区","风顺堂区","嘉模堂区","圣方济各堂区","路氹城"]}]
其中每个大括号可以看作一个对象，每个：前边是属性名，后边是值，每个[]看成一个数组。
测试js代码为：
var data;
 $(function(){
 $.getJSON("citys.json",function(msg){
     data=http://www.mamicode.com/msg;
     $.each(data,function(){
      $("select[name=province]").append("<option>"+this.name+"</option>");
      });
  
      $.each(data[0].cities,function(){
       $("select[name=city]").append("<option>"+this+"</option>");
       })      
    })
 $("select[name=province]").change(function(){         
              $.each(data,function(){
                  if(this.name==$("option:selected").val()){
                      $("select[name=city]").empty();
                      $.each(this.cities,function(){
                      $("select[name=city]").append("<option>"+this+"</option>");
                          })              
                  }
                  })
             })
 });
html里的body里为：
<select name="province">
    </select>
    <br/>
    <select name="city">
  </select>
还有个方法:jQueryload(url, [data], [callback])

$(function(){

 $("a").click(function(){

 $("div").load("top.jsp");

                 });

           })

这里的.load(“”)里面可以放整个页面也可以用过滤选择器 只选择加载其中一个选择器比如

$("div").load("top.jsp .myclass");只加载了其中top.jsp里面的一个类标签！

ajax测试异步提交