我找到了两个函数来使用 Javascript 获取 cookie 数据,一个在 w3schools.com 上和一个 quirksmode.org
我想知道我应该使用哪一个?
例如,我相信我在某处读到某些浏览器在拆分 ;
分号时存在问题?
w3schools:
function getCookie(c_name) {
if (document.cookie.length > 0) {
c_start = document.cookie.indexOf(c_name + "=");
if (c_start != -1) {
c_start = c_start + c_name.length + 1;
c_end = document.cookie.indexOf(";", c_start);
if (c_end == -1) c_end = document.cookie.length;
return unescape(document.cookie.substring(c_start, c_end));
}
}
return "";
}
怪癖模式:
function readCokie(name) {
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for(var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') c = c.substring(1, c.length);
if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
}
return null;
}
最佳答案
W3CSchool 的功能是错误的。如果有多个具有相同后缀的 cookie,它将失败,例如:
ffoo=bar; foo=baz
当您搜索 foo
时,它将返回 ffoo 而不是 foo 的值。
现在我要做的是:首先,您需要了解 cookie 传输的语法。 Netscape 的原始规范(只有副本可用,如 this one at haxx.se )使用分号分隔多个 cookie,而每个名称/值对具有以下语法:
NAME
=
VALUE
This string is a sequence of characters excluding semi-colon, comma and white space. If there is a need to place such data in the name or value, some encoding method such as URL style%XX
encoding is recommended, though no encoding is defined or required.
所以在分号或逗号处拆分 document.cookie
字符串是一个可行的选择。
除此之外,RFC 2109还指定 cookie 由分号或逗号分隔:
cookie = "Cookie:" cookie-version 1*((";" | ",") cookie-value) cookie-value = NAME "=" VALUE [";" path] [";" domain] cookie-version = "$Version" "=" value NAME = attr VALUE = value path = "$Path" "=" value domain = "$Domain" "=" value
虽然两者都是允许的,但逗号是首选,因为它们是 HTTP 中列表项的默认分隔符。
Note: For backward compatibility, the separator in the Cookie header is semi-colon (
;
) everywhere. A server should also accept comma (,
) as the separator between cookie-values for future compatibility.
此外,名称/值对还有一些进一步的限制,因为 VALUE 也可以是 RFC 2616 中指定的带引号的字符串:
attr = token value = token | quoted-string
所以这两个cookie版本需要分开处理:
if (typeof String.prototype.trimLeft !== "function") {
String.prototype.trimLeft = function() {
return this.replace(/^\s+/, "");
};
}
if (typeof String.prototype.trimRight !== "function") {
String.prototype.trimRight = function() {
return this.replace(/\s+$/, "");
};
}
if (typeof Array.prototype.map !== "function") {
Array.prototype.map = function(callback, thisArg) {
for (var i=0, n=this.length, a=[]; i<n; i++) {
if (i in this) a[i] = callback.call(thisArg, this[i]);
}
return a;
};
}
function getCookies() {
var c = document.cookie, v = 0, cookies = {};
if (document.cookie.match(/^\s*\$Version=(?:"1"|1);\s*(.*)/)) {
c = RegExp.$1;
v = 1;
}
if (v === 0) {
c.split(/[,;]/).map(function(cookie) {
var parts = cookie.split(/=/, 2),
name = decodeURIComponent(parts[0].trimLeft()),
value = parts.length > 1 ? decodeURIComponent(parts[1].trimRight()) : null;
cookies[name] = value;
});
} else {
c.match(/(?:^|\s+)([!#$%&'*+\-.0-9A-Z^`a-z|~]+)=([!#$%&'*+\-.0-9A-Z^`a-z|~]*|"(?:[\x20-\x7E\x80\xFF]|\\[\x00-\x7F])*")(?=\s*[,;]|$)/g).map(function($0, $1) {
var name = $0,
value = $1.charAt(0) === '"'
? $1.substr(1, -1).replace(/\\(.)/g, "$1")
: $1;
cookies[name] = value;
});
}
return cookies;
}
function getCookie(name) {
return getCookies()[name];
}
关于Javascript getCookie 函数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4003823/