AJAX 实现form表单提交

<script type="text/javascript" src="resources/js/jquery.js"></script>
<script type="text/javascript" src="resources/js/login.js"></script>



<form id = "form">
       <table align = "center">
           <tr>
               <td>用户名</td><td><input type = "text" id = "userName" name = "userName"></td>
           </tr>
           <tr>
               <td>密码</td><td><input type = "password" id = "userPwd" name = "userPwd"></td>
           </tr>
           <tr>
               <td align = "left"><input id = "submitbtn" type = "submit" value = "登录" style = "background-color: Cyan;color:blue"></td>
               <td align = "right" ><button style = "background-color: Cyan;color:blue"><a href = "/SSM/user/toRegister">注册</a></button></td>
           </tr>
       </table>
     </form>

 1 $(function(){
 2     $("#submitbtn").click(function(){
 3         login();
 4     })
 5 })
 6 function login(){
 7     var userName = $("#userName").val();//获取userName的值
 8     var userPwd = $("#userPwd").val();//获取userPwd的值
 9     $.ajax({
10         url:"user/judgeLogin",
11         type:"POST",
12         data:{"userName":userName,"userPwd":userPwd},
13         dataType:"json", 
14 success:function(returnData){ 
15  alert(returnData);
16  } 
17  })
18 }

 1 function login(){
 2     $.ajax({
 3         url:"user/judgeLogin",
 4         type:"POST",
 5         data:$("#form").serialize(),//表单序列化
 6         dataType:"json",
 7         success:function(returnData){
 8             alert(returnData);
 9         }
10     })
11 }

 1     /**
 2      * 登录判断
 3      * @param userDto
 4      * @return
 5      */
 6     @ResponseBody
 7     @RequestMapping("/judgeLogin")
 8     public String judgeLogin(UserDto userDto) {
 9         int k = userService.judgeLogin(userDto);
10         if(k > 0) {
11             return "--登录成功！--";
12         }else {
13             return "--登录失败！--";
14         }
15     }