1 　　　　//设置cookie
 2 　　　　function setCookie ( name, value, expdays )
 3         {
 4             var expdate = new Date();
 5             //设置Cookie过期日期
 6             expdate.setDate(expdate.getDate() + expdays) ;
 7             //添加Cookie并转码
 8             document.cookie = encodeURI(name) + "=" + escape(value) + ";expires=" + expdate.toUTCString();
 9             
10         }
11         
12         //得到cookie
13         function getCookie ( name )
14         {            
15             //获取name在Cookie中起止位置
16             var start = document.cookie.indexOf(name+"=") ;
17             if ( start != -1 )
18             {
19                 start = start + name.length + 1 ;
20                 //获取value的终止位置
21                 var end = document.cookie.indexOf(";", start) ;
22                 if ( end == -1 )
23                     end = document.cookie.length ;
24                 //截获cookie的value值,并返回
25                 return unescape(document.cookie.substring(start,end)) ;
26             }
27             return "" ;
28         }
29         
30         //删除cookie
31         function delCookie ( name )
32         {
33             setCookie ( name, "", -1 ) ;
34         }

 1 　　　　　　　//提交表单时触发
 2 　　　　　　　function trans() {
 3             
 4             //base64加密
 5             loginForm.password.value = base64encode(loginForm.password.value);
 6             
 7             //获取表单输入:用户名,密码,是否保存密码
 8             var username = document.getElementById("username").value.trim() ;
 9             var password = document.getElementById("password").value.trim() ;
10             var isRmbPwd = document.getElementById("isRmbPwd").checked ;
11             
12             //判断用户名,密码是否为空(全空格也算空)
13              if ( username.length != 0 && password.length != 0 )
14             {
15                 //若复选框勾选,则添加Cookie,记录密码
16                 if ( isRmbPwd == true )
17                 {   
18                     var name = getCookie("username") ;
19                     if(name != username) {
20                         delCookie ("username") ;
21                         delCookie (name) ;
22                     }
23                     setCookie ( "username", username, 30 ) ;
24                     setCookie ( username, password, 30 ) ;
25                 }
26                 //否则清除Cookie
27                 else
28                 {
29                     delCookie ( "username" ) ;
30                     delCookie ( username ) ;
31                 }
32                 return true ;
33             }
34             
35                     
36         }

 1 　　　　　　　//从Cookie获取到用户名
 2             var username = getCookie("username") ;
 3             //如果用户名为空,则给表单元素赋空值
 4             if ( username == "" )
 5             {
 6                 document.getElementById("username").value="" ;
 7                 document.getElementById("password").value="" ;
 8                 document.getElementById("isRmbPwd").checked=false ;
 9             }
10             //获取对应的密码,并把用户名,密码赋值给表单
11             else
12             {
13                 var pwd= getCookie(encodeURI(username)) ;
14                 //base64解密
15                 password = base64decode(pwd);
16                                 
17                 document.getElementById("username").value = username ;
18                 document.getElementById("password").value = password ;
19                 document.getElementById("isRmbPwd").checked = true ;
20             }

 1 　　　　 //参数设置
 2 　　　　 var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 3         var base64DecodeChars = new Array(
 4             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 5             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 6             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
 7             52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
 8             -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
 9             15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
10             -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
11             41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);
12         
13         //加密方法   
14         function base64encode(str) {
15             var out, i, len;
16             var c1, c2, c3;
17             len = str.length;
18             i = 0;
19             out = "";
20             while(i < len) {
21                 c1 = str.charCodeAt(i++) & 0xff;
22                 if(i == len) {
23                     out += base64EncodeChars.charAt(c1 >> 2);
24                     out += base64EncodeChars.charAt((c1 & 0x3) << 4);
25                     out += "==";
26                     break;
27                 }
28                 c2 = str.charCodeAt(i++);
29                 if(i == len) {
30                     out += base64EncodeChars.charAt(c1 >> 2);
31                     out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
32                     out += base64EncodeChars.charAt((c2 & 0xF) << 2);
33                     out += "=";
34                     break;
35                 }
36                 c3 = str.charCodeAt(i++);
37                 out += base64EncodeChars.charAt(c1 >> 2);
38                 out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
39                 out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6));
40                 out += base64EncodeChars.charAt(c3 & 0x3F);
41             }
42             return out;
43         }
44         
45         //解密方法
46         function base64decode(str){
47             var c1, c2, c3, c4;
48             var i, len, out;
49             len = str.length;
50             i = 0;
51             out = "";
52             while (i < len) {
53                 /* c1 */
54                 do {
55                     c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
56                 }
57                 while (i < len && c1 == -1);
58                 if (c1 == -1) 
59                     break;
60                 /* c2 */
61                 do {
62                     c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
63                 }
64                 while (i < len && c2 == -1);
65                 if (c2 == -1) 
66                     break;
67                 out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));
68                 /* c3 */
69                 do {
70                     c3 = str.charCodeAt(i++) & 0xff;
71                     if (c3 == 61) 
72                         return out;
73                     c3 = base64DecodeChars[c3];
74                 }
75                 while (i < len && c3 == -1);
76                 if (c3 == -1) 
77                     break;
78                 out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
79                 /* c4 */
80                 do {
81                     c4 = str.charCodeAt(i++) & 0xff;
82                     if (c4 == 61) 
83                         return out;
84                     c4 = base64DecodeChars[c4];
85                 }
86                 while (i < len && c4 == -1);
87                 if (c4 == -1) 
88                     break;
89                 out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
90             }
91             return out;
92         }

 1 <input id="username" name="username" type="text" class="txt"
 2 value="" placeholder="请输入用户名" value="${username}"/>
 3 
 4 <input id="password" name="password" type="password"
 5 class="txt" value="" placeholder="请输入密码 " />
 6 
 7 <input type="checkbox" id="isRmbPwd" name="isRmbPwd" checked="checked">
 8 <span class="isRmbPwdText">记住密码</span>
 9 
10 <input type="submit" class="login_btn" value="登录" onclick="trans()" />