ajax小结
最近写了几个小的ajax例子，拿出来分享，高手请掠过，代码如下
var xmlHttpRequest;function verify(){ var userName = document.getElementById("userName").value; if (window.XMLHttpRequest) { xmlHttpRequest = new XMLHttpRequest(); } else { if (window.ActiveXObject) { xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP"); } } //注册回调函数 xmlHttpRequest.onreadystatechange = callback; //设置连接信息,用GET方式提交 //xmlHttpRequest.open("GET","AJAXServlet?name=" + userName,true); //发送数据 //xmlHttpRequest.send(null); //设置连接信息用POST方式提交 xmlHttpRequest.open("POST","AJAXXMLServlet",true); //设置http的请求头 xmlHttpRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); //xmlHttpRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); xmlHttpRequest.send("name=" + userName);}function callback(){ //判断对象交互是否完成 if(xmlHttpRequest.readyState == 4){ //判断http交互是否完成 if(xmlHttpRequest.status == 200){ var obj = xmlHttpRequest.responseXML; if(obj){ var messageNodes = obj.getElementsByTagName("message"); if(obj.length > 0){ var message = messageNodes[0].firstChild.nodeValue; document.getElementById("result").innerHTML = message; } }else { window.alert("数据格式不正常"); } }else { window.alert("出错"); } }}import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.ServletException;import java.io.IOException;import java.io.PrintWriter;public class AJAXXMLServlet extends HttpServlet { protected void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException { doGet(httpServletRequest,httpServletResponse); } protected void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException { httpServletRequest.setCharacterEncoding("UTF-8"); httpServletResponse.setContentType("text/xml;charset=UTF-8"); String name = httpServletRequest.getParameter("name"); PrintWriter out = httpServletResponse.getWriter(); StringBuilder sb = new StringBuilder(); sb.append("<message>"); if(null == name || "" == name){ sb.append("用户名不能为空").append("</message>"); out.println(sb.toString()); }else if("xiaoming".equals(name)){ sb.append("用户名[" + name + "]已经存在").append("</message>"); out.println(sb.toString()); }else { sb.append("用户名[" + name + "]可以使用").append("</message>"); out.println(sb.toString()); } out.close(); }}