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[JSP] AJAX 自学练习 请求与显示

开发技术 开发技术 发布于:2021-10-24 12:10 | 阅读数:419 | 评论:0

如下:
request.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
pageEncoding="ISO-8859-1"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
<title>Insert title here</title> 
<script language="javascript"><!-- 
function GetXmlHttpObject(){ 
  var xmlHttp = null; 
  try{ 
    xmlHttp = new XMLHttpRequest(); 
  }catch(e){ 
    try{ 
      xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); 
    }catch(e){ 
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); 
    } 
  } 
  return xmlHttp; 
} 
function showMsg(str){ 
  xmlHttp = GetXmlHttpObject(); 
  if(xmlHttp == null){ 
    alert ("you browser don't support the Ajax"); 
     return; 
  } 
  var url = "response.jsp"; 
  url = url + "?q="+ str; 
  url = url + "&sid ="+ Math.random(); 
  xmlHttp.onreadystatechange = stateChanged; 
  xmlHttp.open("GET", url, true); 
  xmlHttp.send(null); 
} 
function stateChanged() 
{ 
  if(xmlHttp.readyState==4) 
  { 
    document.getElementById("city").value = xmlHttp.responseText; 
  } 
} 
// --></script> 
</head> 
<body> 
<form name="form1" action="" method="post"> 
  <label >City Code:</label> 
  <input type="text" name="code" onblur = "showMsg(this.value)" /> 
  <br></br> 
  <label>City Name:</label> 
  <input type="text" name="city" id="city" ></input> 
</form> 
</body> 
</html>
response.jsp
<%@ page language="java" contentType="text/plain; charset=UTF-8" 
pageEncoding="UTF-8"%> 
<%@ page import="com.lwf.eus.util.*,java.util.*,com.lwf.eus.entity.*,com.lwf.eus.bean.*" %> 
<% 
String code = request.getParameter("q"); 
System.out.println(code); 
if(code.equals("140")) 
  out.print("上海"); 
else if(code.equals("150")) 
  out.print("北京"); 
else if(code.equals("160")) 
  out.print("天津"); 
else 
  out.print("未知地"); 
%>
这里要注意的是由于返回的结果要在文本框中显示,因此在response.jsp中没有<html>等标签,因为测试发现如果有这些标签的话,在cityname文本框中这些标签也会显示。
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