JQuery的AJAX部分的API
（1）jquery对象.load(url,params,function(数据){});（理解）
（2）$.get(url,params,function(数据){},type); 发送get请求的ajax
url:请求的路径
params:请求的参数 参数为key\value的形式 key=value ?{"":"","":""}
function:回调函数 参数就是服务器发送回来的数据
type:返回内容格式，xml, html, script, json, text, _default。 ???以后用"json"
（3）$.post(url,params,function(数据){},type); 发送post请求的ajax
（4）$.ajax([选项]);
选项的可选值:
url:请求路径
type:请求方法
data:发送到服务器的数据
success:fn 成功以后的回调
error:fn 异常之后的回调
dataType:返回内容格式 经常使用json
async:设置是否是异步请求
例如:
$.ajax({ ???????????????url:url, ???????????????type:"post", ???????????????data:params, ???????????????success:function(d){ ???????????????????alert(d.msg); ???????????????}, ???????????????error:function(){}, ???????????????dataType:"json" ???????????????????????????});
若结果为json格式, 打印返回值的时候是一个对象
例如若json为 {"result":"success","msg":"成功"}
获取msg 只需要参数.msg
1、前端ajax
导入js:http://pan.baidu.com/s/1jHLRVTk
<%@ page language="java" contentType="text/html; charset=UTF-8" ???pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><script type="text/javascript" src="${pageContext.request.contextPath }/js/jquery-1.11.3.min.js"></script><title>Insert title here</title><script type="text/javascript"> ???$(function(){ ???????$("#btn").click(function(){ ???????????var url="/day15/jqueryAjax"; ???????????//var params="username=张三"; ???????????var params={"username":"张苏纳"}; ???????????//load方式 ???????????/* $(this).load(url,params,function(d){ ???????????????alert(d); ???????????}); */ ???????????????????????//get方式 ???????????/* $.get(url,params,function(d){ ???????????????alert(d) ???????????}); */ ???????????????????????//post方式 ???????????/* $.post(url,params,function(d){ ???????????????alert(d.msg); ???????????},"json"); */ ???????????????????????//ajax 方式 ???????????$.ajax({ ???????????????url:url, ???????????????type:"post", ???????????????data:params, ???????????????success:function(d){ ???????????????????alert(d.msg); ???????????????}, ???????????????error:function(){}, ???????????????dataType:"json" ???????????????????????????}); ???????}); ???????????})</script></head><body> ???<input type="button" id="btn" value="点我"></body></html>2、servlet
package com.itheima.jquery_ajax;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * jquery的ajax */public class JqueryAjaxServlet extends HttpServlet { ???private static final long serialVersionUID = 1L; ???protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????System.out.println("请求方式:"+request.getMethod()); ???????????????//接受参数 ???????String username = request.getParameter("username"); ???????username=new String(username.getBytes("iso-8859-1"),"utf-8"); ???????System.out.println(username); ???????????????//响应数据 ???????response.getWriter().print("success"); ???} ???protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ???????request.setCharacterEncoding("utf-8"); ???????System.out.println("请求方式:"+request.getMethod()); ???????????????//接受参数 ???????String username = request.getParameter("username"); ???????System.out.println(username); ???????//response.getWriter().print("success"); ???????????????//{"result":"success","msg":"成功"} ???????String s="{\"result\":\"success\",\"msg\":\"成功\"}"; ???????????????//响应数据 ???????response.setContentType("text/html;charset=utf-8"); ???????response.getWriter().print(s); ???}}3、配置web.xml
<servlet> ???<description></description> ???<display-name>JqueryAjaxServlet</display-name> ???<servlet-name>JqueryAjaxServlet</servlet-name> ???<servlet-class>com.itheima.jquery_ajax.JqueryAjaxServlet</servlet-class> ?</servlet> ?<servlet-mapping> ???<servlet-name>JqueryAjaxServlet</servlet-name> ???<url-pattern>/jqueryAjax</url-pattern> ?</servlet-mapping>
问题
<script>是在前还是在后
jQuery选择器
参考：http://www.w3school.com.cn/jquery/jquery_intro.asp
层次选择器 ★ ???????a b:a的所有b后代 ???????a>b:a的所有b孩子 ???????a+b:a的下一个兄弟(大弟弟) ???????a~b:a的所有弟弟 ???基本过滤选择器:★ ???????:frist 第一个 ???????:last 最后一个 ???????:odd ?索引奇数 ???????:even 索引偶数 ???????:eq(index) 指定索引 ???????:gt(index) > ???????:lt(index) < ???内容过滤: ???????:has("选择器"):包含指定选择器的元素 ???可见过滤: ???????:hidden ??在页面不展示元素 一般指 input type="hidden" 和 样式中display:none ???????:visible ????属性过滤器:★ ???????[属性名] ???????[属性名="值"] ???表单过滤: ???????:input ?所有的表单子标签 ?input select textarea button ???????//inputjquery的AJAX
原文地址：http://www.cnblogs.com/Michael2397/p/7643648.html