localStorage是Html5新加入的特性，这个特性主要用来做浏览器本地存储
一、判断浏览器是否支持localStorage
if (!window.localStorage) {
console.log("浏览器不支持localStorage")
} else {
console.log("浏览器支持localStorage")
}
二、往localStorage中写入内容：
var DemoStorage = window.localStorage;
//写入方法1：
DemoStorage.name = "Tom";
//写入方法2：
DemoStorage["age"] = 18;
//写入方法3：
DemoStorage.setItem("hobby", "sport");
console.log(DemoStorage.name,typeof DemoStorage.name);
console.log(DemoStorage.age, typeof DemoStorage.age);
console.log(DemoStorage.hobby, typeof DemoStorage.hobby);
/*输出结果:
Tom string
18 string
sport string*/
以上的代码的例子中：age输入的是一个number，但是输出时是一个string，可见localStorage只能存储string类型的数据。
三、localStorage的删除：
1、删除localStorage中所有的内容：
Storage.clear() 不接受参数，只是简单地清空域名对应的整个存储对象。
var DemoStorage = window.localStorage;
DemoStorage.name = "Tom";
DemoStorage.age = 18;
DemoStorage.hobby = "sport";
console.log(DemoStorage);
//输出：Storage {age: "18", hobby: "sport", name: "Tom", length: 3}
DemoStorage.clear();
console.log(DemoStorage);
//输出: Storage {length: 0}
2、删除某个健值对：
Storage.removeItem() 接受一个参数——你想要移除的数据项的键，然后会将对应的数据项从域名对应的存储对象中移除。
var DemoStorage = window.localStorage;
DemoStorage.name = "Tom";
DemoStorage.age = 18;
DemoStorage.hobby = "sport";
console.log(DemoStorage);
//输出：Storage {age: "18", hobby: "sport", name: "Tom", length: 3}
DemoStorage.removeItem("age");
console.log(DemoStorage);
//输出：Storage {hobby: "sport", name: "Tom", length: 2}
