js 对cookie 的操作

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4 <script>
 5 
 6 function setCookie(cname,cvalue,exdays)
 7 {
 8     if (!navigator.cookieEable) {
 9         alert("cookie 不可用");
10     }else {
11             //获取当前时间
12     var nowTime = new Date();
13     //获取当前时间的毫秒数
14     var time = nowTime.getTime();
15     //根据exdays 算不cookie过期的时间,并设置为这个时间
16     nowTime.setTime(time + exdays * 24 * 60 * 60 * 1000);
17     //设置过期日期
18     var exp = "expires" +"=" + nowTime.toGMTString();
19     //设置cookie
20     document.cookie = cname + "=" + cvalue + ";" + exp;
21     }
22 
23 }
24 
25 function getCookie(cname)
26 {
27 var name = cname + "=";
28 var ca = document.cookie.split(';');
29 
30 for(var i=0; i<ca.length; i++) 
31   {
32   var c = ca[i].trim();
33   if (c.indexOf(name)==0) return c.substring(name.length,c.length);
34   }
35 return "";
36 }
37 
38 function checkCookie()
39 {
40 var user=getCookie("username");
41 if (user!="")
42   {
43   alert("Welcome again " + user);
44   }
45 else 
46   {
47   user = prompt("Please enter your name:","");
48   if (user!="" && user!=null)
49     {
50     setCookie("username",user,30);
51     }
52   }
53 }
54 
55 </script>
56 </head>
57 <body onload="checkCookie()">
58 <button onclick="checkCookie()"> check cookie </button>
59 </body>
60 </html>
原文地址:https://www.cnblogs.com/machao/p/5250990.html