我已经使用这个线程的公认答案很多次了。这是一段很棒的代码:简单且可用。但我通常使用babel和ES6和模块，所以如果你像我一样，这里有一些代码可以复制，以更快地使用ES6开发

接受答案改写为模块与ES6:

export const createCookie = ({name, value, days}) => {
  let expires;
  if (days) {
    let date = new Date();
    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
    expires = '; expires=' + date.toUTCString();
  } else {
    expires = '';
  }
  document.cookie = name + '=' + value + expires + '; path=/';
};

export const getCookie = ({name}) => {
  if (document.cookie.length > 0) {
    let c_start = document.cookie.indexOf(name + '=');
    if (c_start !== -1) {
      c_start = c_start + name.length + 1;
      let 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 '';
};

在这之后，你可以简单地导入它作为任何模块(路径当然可能不同):

import {createCookie, getCookie} from './../helpers/Cookie';

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。

简约且功能齐全的ES6方法:

const setCookie = (name, value, days = 7, path = '/') => {
  const expires = new Date(Date.now() + days * 864e5).toUTCString()
  document.cookie = name + '=' + encodeURIComponent(value) + '; expires=' + expires + '; path=' + path
}

const getCookie = (name) => {
  return document.cookie.split('; ').reduce((r, v) => {
    const parts = v.split('=')
    return parts[0] === name ? decodeURIComponent(parts[1]) : r
  }, '')
}

const deleteCookie = (name, path) => {
  setCookie(name, '', -1, path)
}

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。

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);

通过类似sessionStorage和localStorage的接口:

const cookieStorage = {
  getItem: (key) {
    const cookies = document.cookie.split(';')
      .map(cookie => cookie.split('='))
      .reduce(
        (accumulation, [key, value]) => ({...accumulation, [key.trim()]: value}),
        {}
      )
    
    return cookies[key]
  },
  setItem: (key, value) {
    document.cookie = `${key}=${value}`
  },
}

它的用法cookieStorage。setItem("， ")和cookieStorage.getItem(")。