<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html><head><title>用户名检查</title><scriptlanguage="javascript">functioncreateRequest(url){
http_request =false;if(window.XMLHttpRequest){// a browser is not IE
http_request =newXMLHttpRequest();//create XMLHttpRequest object instance}elseif(window.ActiveXObject){// a browser is IEtry{
http_request =newActiveXObject("Msxml2.XMLHTTP");}catch(e){try{
http_request =newActiveXObject("Microsoft.XMLHTTP");}catch(e){}}}if(!http_request){alert("Cannot create XMLHttpRequest object instance!");returnfalse;}
http_request.onreadystatechange = getResult;// call option function to deal with the result
http_request.open('GET', url,true);// create the connection between the server and client
http_request.send(null);// send a request to a server}functiongetResult(){if(http_request.readyState ===4){// Judge the statue of requestif(http_request.status ===200){// Request successfully,start to deal with the result of return
document.getElementById("toolTip").innerHTML=http_request.responseText;//设置提示内容
document.getElementById("toolTip").style.display="block";//show tooltip}else{// An error occurred on the request pagesalert("The page you requested has errors!");}}}functioncheckUser(userName){if(userName.value===""){alert("please enter user name!");userName.focus();return;}else{createRequest('checkUser.jsp?user='+userName.value);}}</script><styletype="text/css"><!--
#toolTip{position:absolute;left:331px;top:39px;width:100px;height:150px;padding-top:45px;padding-left:25px;padding-right:25px;z-index:1;display:none;color:red;background: #9ce9dd;}
-->
</style></head><body><formmethod="post"action=""name="form"><tablewidth="509"height="352"border="0"align="center"cellpadding="0"cellspacing="0"><tr><tdheight="54"> </td></tr><tr><tdheight="253"valign="top"><divstyle="position:absolute;"><tablewidth="100%"height="250"border="0"cellpadding="0"cellspacing="0"><tr><tdwidth="18%"height="54"align="right"style="color:#8e6723 "><b>用户名:</b></td><tdwidth="49%"><labelfor="username"></label><inputname="username"type="text"id="username"size="32"></td><tdwidth="33%"><inputtype="button"value="Checking username!"onclick="checkUser(form.username)"></td></tr><tr><tdheight="51"align="right"style="color:#8e6723 "><b>密码:</b></td><td><labelfor="pwd1"></label><inputname="pwd1"type="password"id="pwd1"size="35"></td><tdrowspan="2"> <divid="toolTip"></div></td></tr><tr><tdheight="56"align="right"style="color:#8e6723 "><b>确认密码:</b></td><td><labelfor="pwd2"></label><inputname="pwd2"type="password"id="pwd2"size="35"></td></tr><tr><tdheight="55"align="right"style="color:#8e6723 "><b>E-mail:</b></td><tdcolspan="2"><labelfor="email"></label><inputname="email"type="text"id="email"size="45"></td></tr><tr><td> </td><tdcolspan="2"><inputtype="button"value="Login"></td></tr></table></div></td></tr><tr><td> </td></tr></table></form></body></html>
在建立一个 JSP 页面用于检查用户名是否可用,命名为:checkUser.jsp,代码如下:
<%@ page contentType="text/html;charset=UTF-8" language="java"%><%@ page import="java.util.Arrays"%><%
String[] userList={"御承扬","pyc","夜烬天","wyn"};//创建一个一维数组
String user= request.getParameter("user");//获取用户名
Arrays.sort(userList);//对数组排序int result=Arrays.binarySearch(userList,user);//搜索数组if(result>-1){
out.println("Sorry, the username is already registered!");//输出检测结果}else{
out.println("Congratulations, the username has not been registered!");//输出检测结果}%>