cookie 是存储于访问者的计算机中的变量，常用来存储用户名字，密码，日期．
示例：
1 document.cookie="username=John Doe";
2 document.cookie="username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC";
3 document.cookie="username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/";
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <script>
5
6 function setCookie(cname,cvalue,exdays) {
7 var d = new Date();
8 d.setTime(d.getTime() + (exdays*24*60*60*1000));
9 var expires = "expires=" + d.toGMTString();
10 document.cookie = cname+"="+cvalue+"; "+expires;
11 }
12
13 function getCookie(cname) {
14 var name = cname + "=";
15 var ca = document.cookie.split(';');
16 for(var i=0; i<ca.length; i++) {
17 var c = ca[i];
18 while (c.charAt(0)==' ') c = c.substring(1);
19 if (c.indexOf(name) == 0) {
20 return c.substring(name.length, c.length);
21 }
22 }
23 return "";
24 }
25
26 function checkCookie() {
27 var user=getCookie("username");
28 if (user != "") {
29 alert("Welcome again " + user);
30 } else {
31 user = prompt("Please enter your name:","");
32 if (user != "" && user != null) {
33 setCookie("username", user, 30);
34 }
35 }
36 }
37
38 </script>
39 </head>
40 <body onload="checkCookie()">
41 </body>
42 </html>
1 <html>
2 <head>
3 <script type="text/javascript">
4 function getCookie(c_name)
5 {
6 if (document.cookie.length>0)
7 {
8 c_start=document.cookie.indexOf(c_name + "=")
9 if (c_start!=-1)
10 {
11 c_start=c_start + c_name.length+1
12 c_end=document.cookie.indexOf(";",c_start)
13 if (c_end==-1) c_end=document.cookie.length
14 return unescape(document.cookie.substring(c_start,c_end))
15 }
16 }
17 return ""
18 }
19
20 function setCookie(c_name,value,expiredays)
21 {
22 var exdate=new Date()
23 exdate.setDate(exdate.getDate()+expiredays)
24 document.cookie=c_name+ "=" +escape(value)+
25 ((expiredays==null) ? "" : ";expires="+exdate.toGMTString())
26 }
27
28 function checkCookie()
29 {
30 username=getCookie('username')
31 if (username!=null && username!="")
32 {alert('Welcome again '+username+'!')}
33 else
34 {
35 username=prompt('Please enter your name:',"")
36 if (username!=null && username!="")
37 {
38 setCookie('username',username,365)
39 }
40 }
41 }
42 </script>
43 </head>
44
45 <body onLoad="checkCookie()">
46 </body>
47 </html>
1 function createCookie(name, value, days) {
2 var expires;
3
4 if (days) {
5 var date = new Date();
6 date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
7 expires = "; expires=" + date.toGMTString();
8 } else {
9 expires = "";
10 }
11 document.cookie = encodeURIComponent(name) + "=" + encodeURIComponent(value) + expires + "; path=/";
12 }
13
14 function readCookie(name) {
15 var nameEQ = encodeURIComponent(name) + "=";
16 var ca = document.cookie.split(';');
17 for (var i = 0; i < ca.length; i++) {
18 var c = ca[i];
19 while (c.charAt(0) === ' ') c = c.substring(1, c.length);
20 if (c.indexOf(nameEQ) === 0) return decodeURIComponent(c.substring(nameEQ.length, c.length));
21 }
22 return null;
23 }
24
25 function eraseCookie(name) {
26 createCookie(name, "", -1);
27 }