验证用户名是否已存在

来源：互联网发布：全面战争哪代优化最好编辑：程序博客网时间：2024/05/16 23:52

var req;function validate(){var idField=document.getElementById("userId");//var url="ajaxUserRegister.jsp?userId="+escape(idField.value);//escape对中文有问题var url="ajaxUserRegister.jsp?userId="+idField.value;url=encodeURI(url);    url=encodeURI(url);  //写一个不行。如果写一个就是？？？？号。写2个，则输出 %df%a4这种.//alert(url);if(window.XMLHttpRequest){req=new XMLHttpRequest();}else if(window.ActiveXObject){req=new ActiveXObject("Micrsoft.XMLHTTP");}req.open("GET",url,true);req.onreadystatechange=callback;req.send(null);}function callback() {if(req.readyState == 4) {if(req.status == 200) {//alert(req.responseText);var msg = req.responseXML.getElementsByTagName("msg")[0];//alert(msg);        setMsg(msg.childNodes[0].nodeValue);}}}function setMsg(msg){//alert(msg);var mdiv=document.getElementById("usermsg");if(msg=="no"){mdiv.innerHTML="<font color='red'>username exists</font>"}else if(msg=="yes"){mdiv.innerHTML="<font color='green'>you can use the name</font>"}else if(msg=="isNull"){mdiv.innerHTML="<font color='red'>username can't be null</font>"}}<td bgcolor="#D8F6F6" width="32%"><html:text property="userId" size="30" maxlength="20" onblur="validate()"/><span id="usermsg"></span></td>

ajaxUserRegister.jsp：

<%@ page language="java" import="com.wt.bean.User" %><%@ page import="com.wt.action.UserAction;"%><%//response.setCharacterEncoding("UTF-8");response.setContentType("text/xml; charset=UTF-8");//xml,<msg>yes</msg>response.setHeader("tCache-Control","no-cache");//HTTP1.1response.setHeader("Pragma","no-cache");//HTTP1.0response.setDateHeader("Expires",0);//System.out.println("request.getParameter()===="+request.getParameter("userId"));//check databaseString userId=request.getParameter("userId");if(userId==""||userId==null){response.getWriter().write("<msg>isNull</msg>");}else{userId=java.net.URLDecoder.decode(userId,"UTF-8");//chinese <-->EnglishUser user=UserAction.userService.getUser(userId);if(user==null){response.getWriter().write("<msg>yes</msg>");}else{response.getWriter().write("<msg>no</msg>");}}%>

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