ajax 註冊檢查使用者名稱小案例
阿新 • • 發佈：2019-01-08
<%@ page language="java" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>校驗使用者名稱是否存在</title>
<script type="text/javascript" src="./register.js"></script>
</head>
<body
function ajaxFunction(){
var xmlHttp;
try{ // Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}
catch (e){
try{// Internet Explorer
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e){
try{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e){}
}
}
return xmlHttp;
}
window.onload = function(){
document.getElementById("checkusername").onclick = function(){
var username = document.getElementById("username").value;
var xhr = ajaxFunction();
xhr.onreadystatechange = function(){
if(xhr.readyState==4){
if(xhr.status==200){
var data = xhr.responseText;
//獲取文字
document.getElementById("divcheck").innerHTML = data;
}
}
}
xhr.open("post","../RegisterServlet?timeStamp="+new Date().getTime(),true);
xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xhr.send("username="+username);
}
}
package com.cc.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;
@SuppressWarnings("serial")
public class RegisterServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
String username = request.getParameter("username").trim();
System.out.println("username = "+username);
//模擬查詢資料庫
if(username==null||username.equals("")){
out.println("請輸入使用者名稱！");
}else if("sa".equals(username)){
out.println("該使用者名稱已存在！");
}else{
out.println("該使用者名稱可以註冊");
}
}
}