简单的阅读

var getCookie = function (name) {
    var valueStart = document.cookie.indexOf(name + "=") + name.length + 1;
    var valueEnd = document.cookie.indexOf(";", valueStart); 
    return document.cookie.slice(valueStart, valueEnd)
}

一种厚脸皮的、简单的读取cookie的方法可能是这样的:

let username, id; 
eval(document.cookie); 
console.log(username + ", " + id); // John Doe, 123

如果您知道您的cookie包含以下内容，则可以使用此方法:用户名="John Doe";id = 123;。注意，字符串在cookie中需要引号。可能不是推荐的方法，但对测试/学习有效。

JQuery cookie

或纯Javascript:

function setCookie(c_name,value,exdays)
{
   var exdate=new Date();
   exdate.setDate(exdate.getDate() + exdays);
   var c_value=escape(value) + ((exdays==null) ? "" : ("; expires="+exdate.toUTCString()));
   document.cookie=c_name + "=" + c_value;
}

function getCookie(c_name)
{
   var i,x,y,ARRcookies=document.cookie.split(";");
   for (i=0; i<ARRcookies.length; i++)
   {
      x=ARRcookies[i].substr(0,ARRcookies[i].indexOf("="));
      y=ARRcookies[i].substr(ARRcookies[i].indexOf("=")+1);
      x=x.replace(/^\s+|\s+$/g,"");
      if (x==c_name)
      {
        return unescape(y);
      }
   }
}

ES7，使用正则表达式的get()。基于MDN

const Cookie = {
    get: name => {
        let c = document.cookie.match(`(?:(?:^|.*; *)${name} *= *([^;]*).*$)|^.*$`)[1]
        if (c) return decodeURIComponent(c)
    },
    set: (name, value, opts = {}) => {
        /*If options contains days then we're configuring max-age*/
        if (opts.days) {
            opts['max-age'] = opts.days * 60 * 60 * 24;

            /*Deleting days from options to pass remaining opts to cookie settings*/
            delete opts.days 
        }

        /*Configuring options to cookie standard by reducing each property*/
        opts = Object.entries(opts).reduce(
            (accumulatedStr, [k, v]) => `${accumulatedStr}; ${k}=${v}`, ''
        )

        /*Finally, creating the key*/
        document.cookie = name + '=' + encodeURIComponent(value) + opts
    },
    delete: (name, opts) => Cookie.set(name, '', {'max-age': -1, ...opts}) 
    // path & domain must match cookie being deleted 
}

Cookie.set('user', 'Jim', {path: '/', days: 10}) 
// Set the path to top level (instead of page) and expiration to 10 days (instead of session)

用法- Cookie。Get (name, value [， options]): Options支持所有标准cookie选项，并增加了“days”:

path: '/' - any absolute path. Default: current document location, domain: 'sub.example.com' - may not start with dot. Default: current host without subdomain. secure: true - Only serve cookie over https. Default: false. days: 2 - days till cookie expires. Default: End of session. Alternative ways of setting expiration: expires: 'Sun, 18 Feb 2018 16:23:42 GMT' - date of expiry as a GMT string. Current date can be gotten with: new Date(Date.now()).toUTCString() 'max-age': 30 - same as days, but in seconds instead of days.

其他答案使用“expires”而不是“max-age”来支持旧的IE版本。这个方法需要ES7，所以IE7已经出来了(这不是什么大问题)。

注意:像“=”和“{:}”这样有趣的字符被支持作为cookie值，regex处理开头和结尾的空白(来自其他库)。 如果您想存储对象，可以在和JSON之前或之后对它们进行编码。stringify和JSON。解析、编辑上面的内容，或者添加另一个方法。例如:

Cookie.getJSON = name => JSON.parse(Cookie.get(name))
Cookie.setJSON = (name, value, opts) => Cookie.set(name, JSON.stringify(value), opts);

Mozilla创建了一个简单的框架，用于读取和写入cookie，并提供了完整的unicode支持以及如何使用它的示例。

一旦包含在页面中，您可以设置cookie:

docCookies.setItem(name, value);

读饼干:

docCookies.getItem(name);

或者删除cookie:

docCookies.removeItem(name);

例如:

// sets a cookie called 'myCookie' with value 'Chocolate Chip'
docCookies.setItem('myCookie', 'Chocolate Chip');

// reads the value of a cookie called 'myCookie' and assigns to variable
var myCookie = docCookies.getItem('myCookie');

// removes the cookie called 'myCookie'
docCookies.removeItem('myCookie');

查看Mozilla文档中的更多示例和详细信息。饼干页面。

这个简单的js文件的一个版本在github上。

我使用以下函数，这些函数是我从各种来源中找到的最好的函数，并剔除了一些错误或差异。

函数setCookie没有高级选项，只有简单的东西，但代码很容易理解，这总是一个优点:

function setCookie(name, value, daysToLive = 3650) { // 10 years default
  let cookie = name + "=" + encodeURIComponent(value);
  if (typeof daysToLive === "number") {
    cookie += "; max-age=" + (daysToLive * 24 * 60 * 60);
    document.cookie = cookie + ";path=/";
  }
}
function getCookie(name) {
  let cookieArr = document.cookie.split(";");
  for (let i = 0; i < cookieArr.length; i++) {
    let cookiePair = cookieArr[i].split("=");
    if (name == cookiePair[0].trim()) {
      return decodeURIComponent(cookiePair[1].trim());
    }
  }
  return undefined;
}
function deleteCookie(name) {
  setCookie(name, '', -1);
}