引入js-cookie.js
<script src="//cdn.bootcss.com/js-cookie/latest/js.cookie.min.js"></script>
<script>window.Cookies || document.write('<script src="//cdn.jsdelivr.net/npm/js-cookie@2.2.0/src/js.cookie.min.js"><\/script>')
</script>
js-cookie.js常用的API和方法
设置cookie
Cookies.set('name', 'value', { expires: 7, path: '' });//7天过期
Cookies.set('name', { foo: 'bar' });//设置一个json
读取cookie
Cookies.get('name');//获取cookie
Cookies.get(); #读取所有的cookie
删除cookie
Cookies.remove('name'); #删除cookie时必须是同一个路径
下面是国外的介绍
Basic Usage
Create a cookie, valid across the entire site:
Cookies.set('name', 'value');
Create a cookie that expires 7 days from now, valid across the entire site:
Cookies.set('name', 'value', { expires: 7 });
Create an expiring cookie, valid to the path of the current page:
Cookies.set('name', 'value', { expires: 7, path: '' });
Read cookie:
    Cookies.get('name'); // => 'value'
    Cookies.get('nothing'); // => undefined
Read all visible cookies:
Cookies.get(); // => { name: 'value' }
Delete cookie:
Cookies.remove('name');
Delete a cookie valid to the path of the current page:
    Cookies.set('name', 'value', { path: '' });
    Cookies.remove('name'); // fail!
    Cookies.remove('name', { path: '' }); // removed!
IMPORTANT! When deleting a cookie, you must pass the exact same path and domain attributes that were used to set the cookie, unless you're relying on the default attributes.
Note: Removing a nonexistent cookie does not raise any exception nor return any value.
Namespace conflicts
If there is any danger of a conflict with the namespace Cookies, the noConflict method will allow you to define a new namespace and preserve the original one. This is especially useful when running the script on third party sites e.g. as part of a widget or SDK.
// Assign the js-cookie api to a different variable and restore the original "window.Cookies"
    var Cookies2 = Cookies.noConflict();
    Cookies2.set('name', 'value');
Note: The .noConflict method is not necessary when using AMD or CommonJS, thus it is not exposed in those environments.
JSON
js-cookie provides unobtrusive JSON storage for cookies.
When creating a cookie you can pass an Array or Object Literal instead of a string in the value. If you do so, js-cookie will store the string representation of the object according to JSON.stringify:
Cookies.set('name', { foo: 'bar' });
When reading a cookie with the default Cookies.get api, you receive the string representation stored in the cookie:
Cookies.get('name'); // => '{"foo":"bar"}'
Cookies.get(); // => { name: '{"foo":"bar"}' }
When reading a cookie with the Cookies.getJSON api, you receive the parsed representation of the string stored in the cookie according to JSON.parse:
Cookies.getJSON('name'); // => { foo: 'bar' }
Cookies.getJSON(); // => { name: { foo: 'bar' } }
Note: To support IE6-7 (and IE 8 compatibility mode) you need to include the JSON-js polyfill: //github.com/douglascrockford/JSON-js