javascript

Chapter 19: Client - Side Storage
},
return cookieValue;
set: function (name, value, expires, path, domain, secure) {
var cookieText = encodeURIComponent(name) + “=” +
encodeURIComponent(value);
if (expires instanceof Date) {
cookieText += “; expires=” + expires.toGMTString();
}
if (path) {
cookieText += “; path=” + path;
}
if (domain) {
cookieText += “; domain=” + domain;
}
if (secure) {
cookieText += “; secure”;
}
},
document.cookie = cookieText;
unset: function (name, path, domain, secure){
this.set(name, “”, new Date(0), path, domain, secure);
}
};
The CookieUtil.get() method retrieves the value of a cookie with the given name. To do so, it looks
for the occurrence of the cookie name followed by an equal sign in document.cookie . If that pattern is
found, then indexOf() is used to find the next semicolon after that location (which indicates the end of
the cookie). If the semicolon isn ’ t found, this means that the cookie is the last one in the string, so the
entire rest of the string should be considered the cookie value. This value is decoded using
decodeURIComponent() and returned. In the case where the cookie isn ’ t found, null is returned.
The CookieUtil.set() method sets a cookie on the page and accepts several arguments: the name of
the cookie, the value of the cookie, an optional Date object indicating when the cookie should be deleted,
an optional URL path for the cookie, an optional domain for the cookie, and an optional Boolean value
indicating if the secure flag should be added. The arguments are in the order in which they are most
frequently used, and only the first two are required. Inside the method, the name and value are URL -
encoded using encodeURIComponent(), and then the other options are checked. If the expires
argument is a Date object, then an expires option is added using the Date object ’ s toGMTString()
method to format the date correctly. The rest of the method simply builds up the cookie string and sets it
to document.cookie .
There is no direct way to remove existing cookies. Instead, you need to set the cookie again — with the
same path, domain, and secure options — and set its expiration date to some time in the past. The
CookieUtil.unset() method handles this case. It accepts four arguments: the name of the cookie to
remove, an optional path argument, an optional domain argument, and an optional secure argument.
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