cookie 注意点

document.cookie 不能同时设置多个 cookie 值
document.cookie 获取到的是个字符串

简单封装

var manageCookies = {
  set: function(key, value, expTime) {
    document.cookie = key + '=' + value + ';max-age=' + expTime;
    return this;
  },
  delete: function(key) {
    return this.set(key, '', -1);
  },
  get: function(key, cb) {
    // "name=lance; age=26"
    var CookiesArray = document.cookie.split("; ");
    for (var i = 0; i < CookiesArray.length; i++) {
      var CookieItem = CookiesArray[i];
      // ["name=lance", "age=26"]
      var CookieItemArray = CookieItem.split("=");
      if (CookieItemArray[0] === key) {
        cb(CookieItemArray[1]);
        return this;
      }
    }
    cb(undefined);
    return this;
  }
}

manageCookies.set("name", "xiaoming", 10000)
  .set("age", "20", 10000)
  .delete("name")
  .get("age", function(data) {
	  console.log(data);
	});