jsp頁面：

js：

$(document).ready(function(){
        //記住密碼功能
        var str = getCookie("loginInfo");
        str = str.substring(1,str.length-1);
        var username = str.split(",")[0];
        var password = str.split(",")[1];
        //自動填充使用者名稱和密碼
        $("#username").val(username);
        $("#password").val(password);
 });
 //獲取cookie
 function getCookie(cname) {
     var name = cname + "=";
     var ca = document.cookie.split(';');
     for(var i=0; i<ca.length; i++) {
         var c = ca[i];
         while (c.charAt(0)==' ') c = c.substring(1);
         if (c.indexOf(name) != -1) return c.substring(name.length, c.length);
     }
     return "";
 }
 //記住密碼功能
 function remember(){
     var remFlag = $("input[type='checkbox']").is(':checked');
     if(remFlag==true){ //如果選中設定remFlag為1
         //cookie存使用者名稱和密碼,回顯的是真實的使用者名稱和密碼,存在安全問題.
         var conFlag = confirm("記錄賬戶和密碼功能不宜在公共場所(如網咖等)使用,以防密碼洩露.您確定要使用此功能嗎?");
         if(conFlag){ //確認標誌
             $("#remFlag").val("1");
         }else{
             $("input[type='checkbox']").removeAttr('checked');
             $("#remFlag").val("");
         }
     }else{ //如果沒選中設定remFlag為""
         $("#remFlag").val("");
     }
 }

<div class="block">
    <p class="block-heading">使用者登入</p>
    <div class="block-body">
     <form id="login_form"
      action="${pageContext.request.contextPath}/platform/login.htm"
      method="post">
      <input type="hidden" name="remFlag" id="remFlag"/>
      <label>使用者名稱</label>
      <input autocomplete="off" id="username" name="username" value="${userName}" type="text" placeholder="請輸入使用者名稱" class="span12">
      <label>密碼</label>
      <input name="password" id="password" type="password" class="span12" autocomplete="off" value="${userPass}"  placeholder="請輸入用密碼" >
      <label>驗證碼</label>
      <input autocomplete="off" style="width: 150px;" id="code" name="code" type="text"  placeholder="請輸入驗證碼" class="span12"  onblur="document.getElementById('enter').focus();">
      <img alt="驗證碼" id="scode" style="width: 75px; height:30px; margin-bottom: 9px; " src="${pageContext.request.contextPath}/platform/getCode.htmc" >
      <a href="#" onclick="javascript:flushCode();"><font style="font-style:italic;" size="1">看不清?換一張</font></a><br>
      <input name="aaaa" type="checkbox" onclick="remember();">記住賬號和密碼
      <a id="enter" href="#*" class="btn btn-primary pull-right" onclick="toLogin()">立即登入</a>
     </form>
    </div>
   </div>

後臺controller：

String userName = RequestTools.getParameter(request,"username","");
  String userPass = RequestTools.getParameter(request,"password","");
  //記住使用者名稱、密碼功能(注意：cookie存放密碼會存在安全隱患)
        String remFlag = request.getParameter("remFlag");
        if("1".equals(remFlag)){
         //"1"表示使用者勾選記住密碼
            String loginInfo = userName+","+userPass;
            Cookie userCookie=new Cookie("loginInfo",loginInfo);
            userCookie.setMaxAge(30*24*60*60);   //存活期為一個月 30*24*60*60
            userCookie.setPath("/");
            response.addCookie(userCookie);
        }
        request.setAttribute("userName", userName);
        request.setAttribute("userPass", userPass);

就ok了