Ajax简单用例

来源：互联网发布：幽默防网络诈骗标语编辑：程序博客网时间：2024/04/30 10:19

jsp page:

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'Ajax.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

<script type="text/javascript">
  function testAjax(str){
   var xmlhttp;
   if(str==""){
    Document.getElementById("txtHint").innerHTML="";
    return;
   }
   if(window.XMLHttpRequest){
    xmlhttp = new XMLHttpRequest();
   }else{
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");//IE5,IE6浏览器
   }
   xmlhttp.onreadystatechange=function(){
    if(xmlhttp.readyState==4&&xmlhttp.status==200){
     alert("here??????????????????");
     document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
    }
   }
   xmlhttp.open("GET","index.jsp?value="+str,true);
   xmlhttp.send();
  }
</script>
</head>

<body>
    <form action="" style="margin-top:15px;">
<label>请选择一个数字：
<select name="customers" onchange="testAjax(this.value)" style="font-family:Verdana, Arial, Helvetica, sans-serif;">
<option value="0">0</option>
<option value="1 ">1</option>
</select>
</label>
</form>
<br />
<div id="txtHint">数组将在此处列出 ...</div>
</body>
</html>

后台：

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@page import="java.io.PrintWriter"%>
<%@page import="com.sun.org.apache.xalan.internal.xsltc.compiler.sym"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String a = request.getParameter("str");
System.out.println(a+""+"null???????????");
int[] b = new int[]{1,2,3};
b[1] = 1;
b[2] = 2;
String haha ="haha";
if(a.equals("1")){
out.print(b[1]);
}
%>