JSP代码段：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath=request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
Insert title here var xhr; function createXHR(){ if(window.XMLHttpRequest){ xhr =new XMLHttpRequest(); }else{ xhr = new ActiveXObject("Microsoft.XMLHTTP"); } } function checkUn(){ document.getElementById("unInfo").innerHTML=""; var un = document.getElementById("un").value; if(un==""){ document.getElementById("unInfo").innerHTML="用户名不能为空"; return false; } createXHR(); var url="<%=basePath %>CheckUserNameServlet?un="+un; xhr.open("GET",url); xhr.onreadystatechange=function(){ if(xhr.readyState == 4 && xhr.status == 200){ var txt = xhr.responseText; document.getElementById("unInfo").innerHTML = txt; } }; xhr.send(); }
密码:
servlet代码段：
package ed.oracle.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CheckUserNameServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public CheckUserNameServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("GET");
response.setContentType("text/html:charset=UTF-8");
PrintWriter out= response.getWriter();
String un=request.getParameter("un");
if(un != null && un.equals("admin")){
out.println("用户名已存在");
}else{
out.println("用户名可用");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
