jQuery常用的ajax-api-$.post()/$.get()方法-CFANZ编程社区

$.get(url,sendData,function(backData,textStatus,ajax){... ...})
 $.post(url,sendData,function(backData,textStatus,ajax){... ...})

注意：使用get或post方法时，自动进行编码，无需手工编码

以检查注册用户名是否存在为例

jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>检查注册用户名是否存在</title>
  <script type="text/javascript" src="js/jquery-1.8.2.min.js"></script></head>
  <body>
    <!-- 在异步提交的方式下，form标签的action和method属性没有意义 -->
    <form>
      用户名:<input type="text" name="username">
      <input type="button" value="检查">
    </form>
    <span></span>
    <script type="text/javascript">
      $(":button").click(function(){
        var username = $(":text").val();
      var url = "${pageContext.request.contextPath}/servlet/UserServlet";
      var sendData = {
        username : username
      };
      $.post(url,sendData,function(backDate){
        $("span").text(backDate);
      });
      });
    </script>
  </body>
</html>

servlet

public class UserServlet extends HttpServlet {
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    doPost(request, response);
  }

  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    //设置请求的编码
    request.setCharacterEncoding("UTF-8");
    String username = request.getParameter("username");
    String tip = "";
    if("哈哈".equals(username)){
      tip = "用户名已存在";
    }else{
      tip = "可用注册";
    }
    //设置响应的编码，以及格式
    response.setContentType("text/html;charset=UTF-8");
    //获取一个输入流
    PrintWriter pw = response.getWriter();
    //向客户端写进数据
    pw.write(tip);
    pw.flush();
    pw.close();
  }

}