"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Using responseText with innerHTML</title>
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function startRequest() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("GET", "innerHTML.xml", true);
xmlHttp.send(null);
}
function handleStateChange() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
document.getElementById("results").innerHTML = xmlHttp.responseText;
} 这个地方通过DOM API得到元素
}
}
</script>
</head>
<body>
<form action="#">
<input type="button" value="Search for Today's Activities" onclick="startRequest();"/>
</form>
<div id="results"></div>
</body>
</html>
innerHTML.xml
<tr>
<th>Activity Name</th>
<th>Location</th>
<th>Time</th>
</tr>
<tr>
<td>Waterskiing</td>
<td>Dock #1</td>
<td>9:00 AM</td>
</tr>
<tr>
<td>Volleyball</td>
<td>East Court</td>
<td>2:00 PM</td>
</tr>
</table>
接下来一个例子实现的是:通过JSON来做到客户端与服务端的大量数据提交,而不再是简单的 .action?id=1&name=wxy&color=red 而是可以传递类似XML的数据结构,甚至对象的传递
下面的例子看看如何用DOM API来修改页面中的信息
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Dynamically Editing Page Content</title>
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function doSearch() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("GET", "dynamicContent.xml", true);
xmlHttp.send(null);
}
function handleStateChange() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
clearPreviousResults();
parseResults();
}
}
}
function clearPreviousResults() {
var header = document.getElementById("header");
if(header.hasChildNodes()) {
header.removeChild(header.childNodes[0]);
}
var tableBody = document.getElementById("resultsBody");
while(tableBody.childNodes.length > 0) {
tableBody.removeChild(tableBody.childNodes[0]);
}
}
function parseResults() {
var results = xmlHttp.responseXML;
var property = null;
var address = "";
var price = "";
var comments = "";
var properties = results.getElementsByTagName("property");
for(var i = 0; i < properties.length; i++) {
property = properties[i];
address = property.getElementsByTagName("address")[0].firstChild.nodeValue;
price = property.getElementsByTagName("price")[0].firstChild.nodeValue;
comments = property.getElementsByTagName("comments")[0].firstChild.nodeValue;
addTableRow(address, price, comments);
}
var header = document.createElement("h2");
var headerText = document.createTextNode("Results:");
header.appendChild(headerText);
document.getElementById("header").appendChild(header);
document.getElementById("resultsTable").setAttribute("border", "1");
}
function addTableRow(address, price, comments) {
var row = document.createElement("tr");
var cell = createCellWithText(address);
row.appendChild(cell);
cell = createCellWithText(price);
row.appendChild(cell);
cell = createCellWithText(comments);
row.appendChild(cell);
document.getElementById("resultsBody").appendChild(row);
}
function createCellWithText(text) {
var cell = document.createElement("td");
var textNode = document.createTextNode(text);
cell.appendChild(textNode);
return cell;
}
</script>
</head>
<body>
<h1>Search Real Estate Listings</h1>
<form action="#">
Show listings from
<select>
<option value="50000">$50,000</option>
<option value="100000">$100,000</option>
<option value="150000">$150,000</option>
</select>
to
<select>
<option value="100000">$100,000</option>
<option value="150000">$150,000</option>
<option value="200000">$200,000</option>
</select>
<input type="button" value="Search" onclick="doSearch();"/>
</form>
<span id="header">
</span>
<table id="resultsTable" width="75%" border="0">
<tbody id="resultsBody">
</tbody>
</table>
</body>
</html>
<properties>
<property>
<address>812 Gwyn Ave</address>
<price>$100,000</price>
<comments>Quiet, serene neighborhood</comments>
</property>
<property>
<address>3308 James Ave S</address>
<price>$110,000</price>
<comments>Close to schools, shopping, entertainment</comments>
</property>
<property>
<address>98320 County Rd 113</address>
<price>$115,000</price>
<comments>Small acreage outside of town</comments>
</property>
</properties>
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>JSON Example</title>
<script type="text/javascript" src="json.js"></script>
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function doJSON() {
var car = getCarObject();
//Use the JSON JavaScript library to stringify the Car object
var carAsJSON = JSON.stringify(car);
将对象通过JSON转化传递到服务器上去,在那里再进行解析
alert("Car object as JSON: " + carAsJSON);
var url = "JSONExample?timeStamp=" + new Date().getTime();
createXMLHttpRequest();
xmlHttp.open("POST", url, true);
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlHttp.send(carAsJSON);
} 注意这里的POST 与 GET 是不同的。
function handleStateChange() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
parseResults();
}
}
}
function parseResults() {
var responseDiv = document.getElementById("serverResponse");
if(responseDiv.hasChildNodes()) {
responseDiv.removeChild(responseDiv.childNodes[0]);
}
var responseText = document.createTextNode(xmlHttp.responseText);
responseDiv.appendChild(responseText);
}
function getCarObject() {
return new Car("Dodge", "Coronet R/T", 1968, "yellow");
}
function Car(make, model, year, color) {
this.make = make;
this.model = model;
this.year = year;
this.color = color;
}
</script>
</head>
<body>
<br/><br/>
<form action="#">
<input type="button" value="Click here to send JSON data to the server"
onclick="doJSON();"/>
</form>
<h2>Server Response:</h2>
<div id="serverResponse"></div>
</body>
</html>
import java.io.*;
import java.net.*;
import java.text.ParseException;
import javax.servlet.*;
import javax.servlet.http.*;
import org.json.JSONObject;
public class JSONExample extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String json = readJSONStringFromRequestBody(request);
//Use the JSON-Java binding library to create a JSON object in Java
JSONObject jsonObject = null;
try {
jsonObject = new JSONObject(json);
}
catch(ParseException pe) {
System.out.println("ParseException: " + pe.toString());
}
String responseText = "You have a " + jsonObject.getInt("year") + " "
+ jsonObject.getString("make") + " " + jsonObject.getString("model")
+ " " + " that is " + jsonObject.getString("color") + " in color.";
轻松进行类型转换
response.setContentType("text/xml");
response.getWriter().print(responseText);
}
private String readJSONStringFromRequestBody(HttpServletRequest request){
StringBuffer json = new StringBuffer();
String line = null;
try {
BufferedReader reader = request.getReader();
while((line = reader.readLine()) != null) {
json.append(line);
}
}
catch(Exception e) {
System.out.println("Error reading JSON string: " + e.toString());
}
return json.toString();
}
}