js cookie 操作

 1 <html>
 2 <head>
 3   <meta charset="utf-8">
 4   <title>Javascript cookie</title>
 5 <script type="text/javascript">
 6 function getCookie(c_name)
 7 {
 8   alert(document.cookie);
 9   if (document.cookie.length>0)
10   {
11     c_start=document.cookie.indexOf(c_name + "=");
12     if (c_start!=-1)
13     { 
14       c_start=c_start + c_name.length+1;
15       c_end=document.cookie.indexOf(";",c_start);
16       if (c_end==-1) c_end=document.cookie.length
17         return unescape(document.cookie.substring(c_start,c_end));
18     } 
19   }
20   return "";
21 }
22 
23 function setCookie(c_name,value,expiredays)
24 {
25   var exdate=new Date();
26   exdate.setDate(exdate.getDate() + expiredays);
27   document.cookie = c_name + "=" + escape(value) + ((expiredays == null) ? "" : ";expires=" + exdate.toGMTString());
28 }
29 
30 function delCookie(name)
31 {
32   var exp = new Date();
33   exp.setTime(exp.getTime() - 1);
34   var cval = getCookie(name);
35   if (cval != null)
36   {
37     document.cookie= name + "=" + cval + ";expires=" + exp.toGMTString();
38   }
39 }
40 
41 function checkCookie()
42 {
43   var username = getCookie('testJavascriptCookie');
44   if (username != null && username != "")
45   {
46     alert('Welcome again ' + username + '!');
47   }
48   else 
49   {
50     username = prompt('Please enter your name:', "");
51     if (username != null && username != "")
52     {
53       setCookie('testJavascriptCookie', username, 365);
54     }
55   }
56 }
57   
58 </script>
59 </head>
60 
61 <body onLoad="checkCookie();">
62 </body>
63 </html>