cookie_0">cookie简单介绍

1. cookie的特点

   1.cookie一般有大小限制为4kb，
   2.限制同一域名数量为50个
   3.读取有域名限制
   4.时效性
   

2. cookie 使用

   //添加cookie
   document.cookie = “key=value”; // 一次写入一个键值对
   //读取cookie 
   document.cookie //获得所有cookie  分号分割
   
   //expires  时效
   document.cookie = `${key}=${value};${expires}=${expires}`
   //path  路径 '/'
   document.cookie = `${key}=${value};expires=${expires};path=${path}`
   //domain  域名 'www.csdn.com'
   	document.cookie = `${key}=${value};expires=${expires};path=${path};domain=${domain}`
   

cookie__26">cookie 封装

    /**
     * @description:  设置cookie
     * @param {*} key cookie 的键
     * @param {*} value  cookie 值
     * @param {*} expires 时间/天
     * @param {*} path 域名下路径
     * @return {*}
     */
    function setCookie(key, value, expires, path, domain) {
      if (typeof expires === "number") {
        var date = new Date();
        date.setDate(date.getDate() + expires);
      }
      // 1.处理默认保存的路径
      var index = window.location.pathname.lastIndexOf("/");
      var currentPath = window.location.pathname.slice(0, index);
      path = path || currentPath;
      // 2.处理默认保存的domain
      domain = domain || document.domain;
      document.cookie =`${key}=${value};expires=${date};path=${path};domain=${domain}`
    }

    /**
     * @description: 获取cookie
     * @param {*} key  要获取的cookie的键
     * @return {*}
     */
    function getCookie(key){
      let cookieStr = document.cookie
      console.log(cookieStr);
      cookieArray = cookieStr.split(';')
      console.log(cookieArray);
      for (let i = 0; i < cookieArray.length; i++) {
          let temp = cookieArray[i].split('=')
          if(temp[0].trim() === key){
            return temp[1]
          }
      }
      
    }
     /**
     * @description: 删除cookie
     * @param {*} key 键
     * @param {*} path 路径
     * @return {*}
     */
    function removeCookie(key,path){
      setCookie(key,1,-1,path)
    }