Posts

=================================

Working with cookies | DzQ39 |

This is a quick summary of how to work with cookies.

The code below is from https://www.w3schools.com/js/js_cookies.asp.


 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
<!DOCTYPE html>
<html>
<head>
<script>

function setCookie(cname,cvalue,exdays) {
var d = new Date();
d.setTime(d.getTime() + (exdays*24*60*60*1000));
var expires = "expires=" + d.toGMTString();
document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}

function getCookie(cname) {
var name = cname + "=";
var decodedCookie = decodeURIComponent(document.cookie);
var ca = decodedCookie.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) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}

function checkCookie() {
var user=getCookie("username");
if (user != "") {
alert("Welcome again " + user);
} else {
user = prompt("Please enter your name:","");
if (user != "" && user != null) {
setCookie("username", user, 30);
}
}
}

</script>
</head>
<body onload="checkCookie()">
</body>
</html>

Note that Chrome doesn't support local cookies. That is, the above code won't work if it's run from a local storage (it will run fine if it's run from a server). However, Internet Explorer, Firefox, Safari, and Opera don't have such problem. For detail, see the discussion at https://productforums.google.com/forum/#!topic/chrome/iow88FsnNhQ.