javascript记住用户名和登录密码（两种方式）

下面主要通过代码给大家展示下javascript记住用户名和登录密码，具体代码内容请看下文。

第一种方式：

CONTENT
    login.html
    welcome.html
    cookie.js
    common.js
login.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>login</title>
<script type="text/javascript" src="cookie.js"></script>
<script type="text/javascript" src="common.js"></script>
</head>
<body>
<form action="">
<p>
  <span>UserName:</span>
  <input id="userName" type="text" value=""/></p>
<p>
  <span>Password:</span>
  <input id="password" type="password" value=""/></p>
<p>
  <span style="font-size:12px; color:blue;">记住密码</span>
  <input id="saveCookie" type="checkbox" value="" /></p>
<p>
  <input id="submit" type="button" value="GO" />
</p>
</form>
</body>
</html>

welcome.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>welcome</title>
</head>
<body>
<h1>Welcome!</h1>
<a href="login.html">点击返回登陆框</a>
</body>
</html>
cookie.js
//新建cookie。
//hours为空字符串时,cookie的生存期至浏览器会话结束。hours为数字0时,建立的是一个失效的cookie,这个cookie会覆盖已经建立过的同名、同path的cookie（如果这个cookie存在）。
function setCookie(name,value,hours,path){
  var name = escape(name);
  var value = escape(value);
  var expires = new Date();
   expires.setTime(expires.getTime() + hours*3600000);
   path = path == "" ? "" : ";path=" + path;
   _expires = (typeof hours) == "string" ? "" : ";expires=" + expires.toUTCString();
   document.cookie = name + "=" + value + _expires + path;
}
//获取cookie值
function getCookieValue(name){
  var name = escape(name);
  //读cookie属性，这将返回文档的所有cookie
  var allcookies = document.cookie;
  //查找名为name的cookie的开始位置
   name += "=";
  var pos = allcookies.indexOf(name);
  //如果找到了具有该名字的cookie，那么提取并使用它的值
  if (pos != -1){                       //如果pos值为-1则说明搜索"version="失败
    var start = pos + name.length;         //cookie值开始的位置
    var end = allcookies.indexOf(";",start);    //从cookie值开始的位置起搜索第一个";"的位置,即cookie值结尾的位置
    if (end == -1) end = allcookies.length;    //如果end值为-1说明cookie列表里只有一个cookie
    var value = allcookies.substring(start,end); //提取cookie的值
    return (value);              //对它解码
     }
  else return "";                //搜索失败，返回空字符串
}
//删除cookie
function deleteCookie(name,path){
  var name = escape(name);
  var expires = new Date(0);
   path = path == "" ? "" : ";path=" + path;
   document.cookie = name + "="+ ";expires=" + expires.toUTCString() + path;
}

common.js

function $(objStr){return document.getElementByIdx_x_x(objStr);}
window.onload = function(){
  //分析cookie值，显示上次的登陆信息
  var userNameValue = getCookieValue("userName");
   $("userName").value = userNameValue;
  var passwordValue = getCookieValue("password");
   $("password").value = passwordValue;
  //写入点击事件
   $("submit").onclick = function()
   {
    var userNameValue = $("userName").value;
    var passwordValue = $("password").value;
    //服务器验证（模拟）
    var isAdmin = userNameValue == "admin" && passwordValue =="123456";
    var isUserA = userNameValue == "userA" && passwordValue =="userA";
    var isMatched = isAdmin || isUserA;
    if(isMatched){
      if( $("saveCookie").checked){
         setCookie("userName",$("userName").value,24,"/");
         setCookie("password",$("password").value,24,"/");
       }
       alert("登陆成功,欢迎你," + userNameValue + "!");
       self.location.replace("welcome.html");
     }
    else alert("用户名或密码错误，请重新输入！");
   }
}

第二种方式：

<script type="text/javascript">
window.onload=function onLoginLoaded() {
if(isPostBack == "False") {
GetLastUser();
}
}
function GetLastUser() {
var id = "49BAC005-7D5B-4231-8CEA-16939BEACD67";//GUID标识符
var usr = GetCookie(id);
if (usr != null) {
document.getElementById('txtUserName').value = usr;
}
else {
document.getElementById('txtUserName').value = "001";
}
GetPwdAndChk();
}
//点击登录时触发客户端事件
function SetPwdAndChk() {
//取用户名
var usr = document.getElementById('txtUserName').value;
alert(usr);
//将最后一个用户信息写入到Cookie
SetLastUser(usr);
//如果记住密码选项被选中
if(document.getElementById('chkRememberPwd').checked == true) {
//取密码值
var pwd = document.getElementById('txtPassword').value;
alert(pwd);
var expdate = new Date();
expdate.setTime(expdate.getTime() + 14 * (24 * 60 * 60 * 1000));
//将用户名和密码写入到Cookie
SetCookie(usr, pwd, expdate);
}
else {
//如果没有选中记住密码,则立即过期
ResetCookie();
}
}
function SetLastUser(usr) {
var id = "49BAC005-7D5B-4231-8CEA-16939BEACD67";
var expdate = new Date();
//当前时间加上两周的时间
expdate.setTime(expdate.getTime() + 14 * (24 * 60 * 60 * 1000));
SetCookie(id, usr, expdate);
}
//用户名失去焦点时调用该方法
function GetPwdAndChk() {
var usr = document.getElementById('txtUserName').value;
var pwd = GetCookie(usr);
if (pwd != null) {
document.getElementById('chkRememberPwd').checked = true;
document.getElementById('txtPassword').value = pwd;
}
else {
document.getElementById('chkRememberPwd').checked = false;
document.getElementById('txtPassword').value = "";
}
}
//取Cookie的值
function GetCookie(name) {
var arg = name + "=";
var alen = arg.length;
var clen = document.cookie.length;
var i = 0;
while (i < clen) {
var j = i + alen;
//alert(j);
if (document.cookie.substring(i, j) == arg) return getCookieVal(j);
i = document.cookie.indexOf(" ", i) + 1;
if (i == 0) break;
}
return null;
}
var isPostBack = "<%= IsPostBack %>";
function getCookieVal(offset) {
var endstr = document.cookie.indexOf(";", offset);
if (endstr == -1) endstr = document.cookie.length;
return unescape(document.cookie.substring(offset, endstr));
}
//写入到Cookie
function SetCookie(name, value, expires) {
var argv = SetCookie.arguments;
//本例中length = 3
var argc = SetCookie.arguments.length;
var expires = (argc > 2) ? argv[2] : null;
var path = (argc > 3) ? argv[3] : null;
var domain = (argc > 4) ? argv[4] : null;
var secure = (argc > 5) ? argv[5] : false;
document.cookie = name + "=" + escape(value) + ((expires == null) ? "" : ("; expires=" + expires.toGMTString())) + ((path == null) ? "" : ("; path=" + path)) + ((domain == null) ? "" : ("; domain=" + domain)) + ((secure == true) ? "; secure" : "");
}
function ResetCookie() {
var usr = document.getElementById('txtUserName').value;
var expdate = new Date();
SetCookie(usr, null, expdate);
}
</script>
</head>
<body>
<form id="form1">
<div>
用户名:<input type="text" ID="txtUserName" onblur="GetPwdAndChk()">
<input type="password" ID="txtPassword">
密码：
<input type="checkbox" ID="chkRememberPwd" />
记住密码
<input type="button" OnClick="SetPwdAndChk()" value="进入"/>
</div>
</form>
</body>

以上就是用两种方式展示javascript记住用户名和登录密码的全部代码，没有来得及整理运行效果图，希望大家能够喜欢。