创建名为remember-me.js的JS文件
function onLoginLoaded() {
      if (isPostBack == "False") {
            GetLastUser();
      }
}
function GetLastUser() {
      var id = "49BAC005-7D5B-4231-8CEA-16939BEACD67";
      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;
      //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;
            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);
}



在页面中引用<script src="common/scripts/remember-me.js" />JS文件

<input id="txtUserName" class="home_login_name" type="text" value="能助手帐户地址"  onblur="GetPwdAndChk()" />
<input id="txtPassword" class="home_login_password" type="text" value="密码" />
<img src="common/p_w_picpaths/login_button.gif" alt="提交"  onclick="SetPwdAndChk()" />
<input id="chkRememberPwd" class="home_checkbox" type="checkbox" value="" />记住我