JavaScript使用cookie实现记住账号密码功能

很多登录功能上都有个“记住密码”的功能，其实无非就是对cookie的读取。

下面展示这个功能的代码，原作者已无法考究。。。。

测试方法：直接输入账号密码，提交后，刷新页面，再输入同样的账号，就可以显示

<!DOCTYPE HTML>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>js COOKIE 记住帐号或密码</title>
<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>
</html>