传统·ajax实现用户名是否被注册

来源：互联网发布：面霜推荐知乎编辑：程序博客网时间：2024/05/28 17:06

<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'login.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

<script language="javascript">
  function checkUser(userName){
   if(userName.value==""){
    alert("请输入用户名");userName.focus();return;
   }else{
    createRequest('checkuser.jsp?user='+userName.value);
   }
  }
  function createRequest(url){
   http_request = false;
   if(window.XMLHttpRequest){
    http_request = new XMLHttpRequest();
   }else if(window.ActiveXObject){
     try {
                http_request = new ActiveXObject("Msxml2.XMLHTTP"); //创建XMLHttpRequest对象
            } catch (e) {
                try {
                    http_request = new ActiveXObject("Microsoft.XMLHTTP"); //创建XMLHttpRequest对象
               } catch (e) {}
            }
   }
   if(!http_request){
    alert("不能创建XMLHttpRequest对象");
    return false;
   }
   http_request.onreadystatechange = getResult;
   http_request.open('post',url,true);
   http_request.send(null);
  }
  function getResult(){
   if(http_request.readyState ==4){
    if(http_request.status ==200){
      alert(http_request.responseText);
    }
    else{
     alert("你请求的页面有错误");
    }
   }
  }
</script>
</head>

<body>
    <tr>
    <form name="form1" method="post" action="">
<table width="402" border="0" align="center" cellpadding="0" cellspacing="1" bordercolor="#FFFFFF" bordercolorlight="#FFFFFF" bordercolordark="#777777" bgcolor="#999999">
    <tr>
      <td height="30" colspan="2" bgcolor="#EEEEEE">·用户注册</td>
    </tr>
    <tr>
      <td width="113" height="30" align="center" bgcolor="#FFFFFF">用户名：</td>
      <td width="387" bgcolor="#FFFFFF"><input name="username" type="text" id="username" size="30">
        <input name="b_checkUser" type="button" class="btn_grey" id="b_checkUser" value="检测用户名" onClick="checkUser(this.form.username);"></td>
    </tr>
    <tr>
      <td height="30" align="center" bgcolor="#FFFFFF">密    码：</td>
      <td bgcolor="#FFFFFF"><input name="pwd" type="password" id="pwd" size="30"></td>
    </tr>
    <tr>
      <td height="30" align="center" bgcolor="#FFFFFF">确认密码：</td>
      <td bgcolor="#FFFFFF"><input name="pwd1" type="password" id="pwd1" size="30"></td>
    </tr>
    <tr>
      <td height="40" colspan="2" align="center" bgcolor="#FFFFFF"><input name="b_submit" type="submit" class="btn_grey" id="b_submit" value="提交">
         
      <input name="b_reset" type="reset" class="btn_grey" id="b_reset" value="重置"></td>
    </tr>
</table>
</form>
</body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="GBK" %>
<%
String[] userList={"明日科技","mr","wgh","mrsoft"};
String user=new String(request.getParameter("user").getBytes("ISO-8859-1"),"GBK");   //获取用户名
out.println(user);
Arrays.sort(userList);        //对数组排序
int result=Arrays.binarySearch(userList,user);  //搜索数组
if(result>-1){
  out.println("很抱歉，该用户名已经被注册！");  //输出检测结果
}else{
  out.println("恭喜您，该用户名没有被注册！");  //输出检测结果
}
%>

此外，javascript在html代码中不分大小写，，arrays找不到返回-1

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